[editor] Fix deleting elements when they don't have focus

All elements get the 'aspect-inserted-element' class, which is checked 
before deleting the element.

projects/editor/src/app/components/unit-view/page-view/canvas/canvas-element-overlay.ts

@@ -54,8 +54,9 @@ export abstract class CanvasElementOverlay implements OnInit, OnDestroy {
 
   @HostListener('window:keydown', ['$event'])
   handleKeyDown(event: KeyboardEvent): void {
-    if (!(event.target as Element).tagName.includes('input'.toUpperCase()) &&
-        !(event.target as Element).tagName.includes('textarea'.toUpperCase()) &&
+    if ((event.target as Element).parentElement &&
+        (event.target as Element).parentElement!.parentElement &&
+        (event.target as Element).parentElement!.parentElement!.className.indexOf('aspect-inserted-element') > -1 &&
         event.key === 'Delete') {
       this.selectionService.selectedElements
         .pipe(take(1))

projects/editor/src/app/components/unit-view/page-view/canvas/static-canvas-overlay.component.ts

@@ -26,7 +26,7 @@ import { CanvasElementOverlay } from './canvas-element-overlay';
           <mat-icon>aspect_ratio</mat-icon>
           <div *cdkDragPlaceholder></div>
         </div>
-        <div [style.width.px]="element.width"
+        <div class="aspect-inserted-element" [style.width.px]="element.width"
              [style.overflow]="'auto'"
              [style.height.px]="element.height">
           <ng-template #elementContainer></ng-template>