Make InputElement labe optional and remove it from cloze children

Cloze elements are displayed inline and have no way to show a label.

projects/common/models/uI-element.ts

@@ -62,7 +62,7 @@ export abstract class UIElement {
 }
 
 export abstract class InputElement extends UIElement {
-  label: string;
+  label?: string;
   value: InputElementValue;
   required: boolean;
   requiredWarnMessage: string;

projects/common/ui-elements/drop-list-simple/drop-list-simple.ts

@@ -23,6 +23,8 @@ export class DropListSimpleElement extends InputElement implements FontElement,
     this.fontProps = initFontElement(serializedElement);
     this.surfaceProps = initSurfaceElement(serializedElement);
 
+    delete this.label;
+
     this.value = serializedElement.value as string[] || [];
     this.height = serializedElement.height || 100;
     this.surfaceProps.backgroundColor =

projects/common/ui-elements/textfield-simple/text-field-simple-element.ts

@@ -18,6 +18,8 @@ export class TextFieldSimpleElement extends InputElement implements FontElement,
     this.fontProps = initFontElement(serializedElement);
     this.surfaceProps = initSurfaceElement(serializedElement);
 
+    delete this.label;
+
     this.height = serializedElement.height || 25;
   }
 }

projects/common/ui-elements/toggle-button/toggle-button.ts

@@ -21,6 +21,8 @@ export class ToggleButtonElement extends InputElement implements FontElement, Su
     this.fontProps = initFontElement(serializedElement);
     this.surfaceProps = initSurfaceElement(serializedElement);
 
+    delete this.label;
+
     this.height = serializedElement.height as number || 25;
     this.surfaceProps.backgroundColor =
       serializedElement.surfaceProps?.backgroundColor as string ||