[editor] Remove placeholder from visibility rules inputs

projects/editor/src/app/components/dialogs/visibility-rules-dialog/visibility-rule-editor.component.html

@@ -24,7 +24,6 @@
   <mat-form-field>
     <mat-label>{{'section.value' | translate}}</mat-label>
     <input matInput
-           [placeholder]="'section.value' | translate"
            [(ngModel)]="visibilityRule.value"
            (ngModelChange)="visibilityRuleChange.emit(visibilityRule)">
   </mat-form-field>