Laravel 9 update Form that contain input file for CV

I have been trying to update a form that has a resume file input. I want users to only change the file if they are make mistake of uploading a wrong resume but the page refrresh and when i debug using dd i can not see in my json respond the cv input with all other fields here is my current code

InterviewController.php

public function update(Request $request, $id)
   {

       
       // Validate the form data
       $request->validate([
           'candidat_name' => 'required|string',
           'poste' => 'required|string',
           'interview_time' => 'required|date_format:H:i',
           'interview_date' => 'required|date',
           'cv' => 'nullable|file|mimes:pdf,doc,docx|max:2048',
           'description' => 'required|string',
       ]);
   
       // Find the existing Interview model instance
       $interview = Interview::findOrFail($id);
   
       // Update interview attributes
       $interview->candidat_name = $request->input('candidat_name');
       $interview->poste = $request->input('poste');
       $interview->interview_time = $request->input('interview_time');
       $interview->interview_date = $request->input('interview_date');
       $interview->description = $request->input('description');
   
       // Handle file upload if a new CV is provided
       if ($request->hasFile('cv')) {
           // Delete the existing CV file if it exists
           if ($interview->cv) {
               Storage::delete('public/' . $interview->cv);
           }
           $cv = $request->file('cv');
           $cvPath = $cv->store('cvs', 'public');
           $interview->cv = $cvPath;
       } else {
           // If no new file is provided, keep the existing file path
           $interview->cv = $interview->cv;
       }
   
       // Save the updated interview
       $interview->save();
   
       // Redirect with a success message
       return redirect()->route('interviews.index')->with('success', 'Interview updated successfully.');
   } 

index.blade.php

Here is my form

@foreach ($interviews as $interview)
<div class="modal fade bd-example-modal-lg" id="editModal-{{ $interview->id }}" tabindex="-1" role="dialog" aria-labelledby="myLargeModalLabel" aria-hidden="true">
    <div class="modal-dialog modal-lg" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="myLargeModalLabel">Modifier Informations</h5>
                <button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close">
                  <svg aria-hidden="true" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-x"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg>
                </button>
            </div>

            
            <div class="modal-body">
                <form action="{{ route('interviews.update', $interview->id) }}" method="POST" enctype="multipart/form-data">                   
                    @csrf
                    @method('PUT')
                    <div class="row mb-3">
                        <div class="col">
                            <label for="">Candidat</label>
                            <input type="text" class="form-control form-control-sm" name="candidat_name" id="candidat_name" value="{{ $interview->candidat_name }}" placeholder="Nom & Prénom">
                        </div>
                        <div class="col">
                            <label for="">Poste</label>
                            <select class="form-select form-control-sm" name="poste" id="poste" required>
                                <option value="" disabled selected>Sélectionner Poste</option>
                                @foreach ($jobs as $job)
                                    <option value="{{ $job->poste }}" {{ $interview->poste == $job->poste ? 'selected' : '' }}>{{ $job->poste }}</option>
                                @endforeach
                            </select>
                        </div>
                    </div>
                    <div class="row mb-2">
                        <div class="col">
                            <label for="">Heure d'entretien</label>
                            <input type="time" class="form-control form-control-sm" name="interview_time" id="interview_time" value="{{ $interview->interview_time }}" placeholder="Nom & Prénom">
                        </div>
                        <div class="col">
                            <label for="">Date d'entretien</label>
                            <input type="date" class="form-control form-control-sm" name="interview_date" id="interview_date" value="{{ $interview->interview_date }}">
                        </div>
                    </div>
                    <div class="mb-3">
                        <label for="">Curriculum Vitae</label>
                      
                        <input class="form-control file-upload-input" type="file" name="cv" id="formFile">
                    </div>
                    
                    <div class="form-group mb-4">
                        <label for="exampleFormControlTextarea1">Description</label>
                        <textarea class="form-control" id="exampleFormControlTextarea1" rows="3" name="description">{{ $interview->description }}</textarea>
                    </div>
                </div>
                <div class="modal-footer">
                    <input type="button" value="{{__('Annuler')}}" class="btn  btn-dark" data-bs-dismiss="modal">
                    <input type="submit" value="{{__('Modifier')}}" class="btn  btn-primary">
                </div>
            </form>
        </div>
    </div>
</div> 
@endforeach