Disable select by evaluating if another input value is null or not

                    Select::make('company_id')
                        ->relationship('company', 'legal_name')
                        ->searchable(['legal_name', 'vat_number'])
                        ->preload()
                        ->label('Azienda destinataria'),
                    Select::make('company_contact_id')
                        ->relationship('company_contact', 'full_name', fn (Builder $query, $get) => $query->where('company_id', $get('company_id')))
                        ->searchable(['name', 'surname', 'email'])
                        ->preload()
                        ->label('Referente aziendale')
                        ->disabled(fn ($get) => $get('company_id') == null)
                        ->required()]),