fix(cdk/table): revert breaking change of CdkTable constructor

With Release 13.1.2 a breaking change was introduced in cdk/table.
If a consumer has a class which extends CdkTable, compilation breaks
due to the newly introduced required constructor parameter _ngZone.
See PR: #23885

Author: jeripeierSBB

src/cdk/table/table.ts

@@ -531,7 +531,7 @@ export class CdkTable<T> implements AfterContentChecked, CollectionViewer, OnDes
      * @breaking-change 14.0.0
      */
     @Optional()
-    protected readonly _ngZone: NgZone,
+    protected readonly _ngZone?: NgZone,
   ) {
     if (!role) {
       this._elementRef.nativeElement.setAttribute('role', 'table');