Remove useless CompoundElement component wrapper-element and CSS rules

- Extra span element around cloze child elements served no visible 
purpose. It also makes sense that an inline div is not inside of a span, 
which is meant for text.
- CSS rules were overengineered and in part shadowed (and thereby 
pointless) by element styles from the template.
This is also in preparation for the DropList styling overhaul.

projects/common/components/compound-elements/cloze/cloze.component.ts

@@ -155,14 +155,14 @@ import { ClozeElement } from 'common/models/elements/compound-elements/cloze/clo
                [style.height]="'1em'"
                [style.vertical-align]="'middle'">
         </ng-container>
-        <span *ngIf="['ToggleButton', 'DropList', 'TextField', 'Button'] | arrayIncludes:subPart.type">
-          <aspect-compound-child-overlay [style.display]="'inline-block'"
-                                         [parentForm]="parentForm"
-                                         [element]="$any(subPart).attrs.model"
-                                         [editorMode]="editorMode"
-                                         (elementSelected)="childElementSelected.emit($event)">
-          </aspect-compound-child-overlay>
-        </span>
+        <aspect-compound-child-overlay
+          *ngIf="['ToggleButton', 'DropList', 'TextField', 'Button'] | arrayIncludes:subPart.type"
+          [style.display]="'inline-block'"
+         [parentForm]="parentForm"
+         [element]="$any(subPart).attrs.model"
+         [editorMode]="editorMode"
+         (elementSelected)="childElementSelected.emit($event)">
+        </aspect-compound-child-overlay>
       </ng-container>
     </ng-template>
   `,

projects/common/components/compound-elements/cloze/compound-child-overlay.component.ts

@@ -44,11 +44,8 @@ import { ValueChangeElement } from 'common/models/elements/element';
     </div>
   `,
   styles: [
-    ':host {vertical-align: middle;}',
-    ':host > div {border-radius: 3px;}',
-    ':host div > * {display: inline-block; padding-bottom: 2px; box-sizing: border-box;}',
-    'aspect-drop-list, aspect-text-field-simple {width: 100%; height: 100%;}',
-    'aspect-drop-list {line-height: unset; vertical-align: top;}'
+    ':host div > * {display: inline-block;}',
+    'aspect-drop-list {vertical-align: middle;}'
   ]
 })
 export class CompoundChildOverlayComponent { // TODO rename to ClozeChildOverlay