fix(cdk/drag-drop): allow using cdkDragRootElement w/ comment tag

Author: lekhmanrus

src/cdk/drag-drop/directives/drag.ts

@@ -330,9 +330,11 @@ export class CdkDrag<T = any> implements AfterViewInit, OnChanges, OnDestroy {
 
   /** Syncs the root element with the `DragRef`. */
   private _updateRootElement() {
-    const element = this.element.nativeElement;
+    const element = this.element.nativeElement as HTMLElement;
+    // Comment tag doesn't have closest method, so use parent's one.
+    const closestFn = element.closest || element.parentElement?.closest;
     const rootElement = this.rootElementSelector ?
-      element.closest<HTMLElement>(this.rootElementSelector) : element;
+      closestFn<HTMLElement>(this.rootElementSelector) : element;
 
     if (rootElement && (typeof ngDevMode === 'undefined' || ngDevMode)) {
       assertElementNode(rootElement, 'cdkDrag');