fix(cdk/drag-drop): breaking changes for v22

Breaking changes for the `cdk/drag-drop` packages in v22.

BREAKING CHANGE:
* The `event` parameter of `DropListRef.drop` is now required.

Author: crisbeto

goldens/cdk/drag-drop/index.api.md

@@ -497,7 +497,7 @@ export class DropListRef<T = any> {
     data: T;
     disabled: boolean;
     dispose(): void;
-    drop(item: DragRef, currentIndex: number, previousIndex: number, previousContainer: DropListRef, isPointerOverContainer: boolean, distance: Point, dropPoint: Point, event?: MouseEvent | TouchEvent): void;
+    drop(item: DragRef, currentIndex: number, previousIndex: number, previousContainer: DropListRef, isPointerOverContainer: boolean, distance: Point, dropPoint: Point, event: MouseEvent | TouchEvent): void;
     readonly dropped: Subject<{
         item: DragRef;
         currentIndex: number;

src/cdk/drag-drop/drop-list-ref.ts

@@ -301,8 +301,6 @@ export class DropListRef<T = any> {
    *    container when the item was dropped.
    * @param distance Distance the user has dragged since the start of the dragging sequence.
    * @param event Event that triggered the dropping sequence.
-   *
-   * @breaking-change 15.0.0 `previousIndex` and `event` parameters to become required.
    */
   drop(
     item: DragRef,
@@ -312,7 +310,7 @@ export class DropListRef<T = any> {
     isPointerOverContainer: boolean,
     distance: Point,
     dropPoint: Point,
-    event: MouseEvent | TouchEvent = {} as any,
+    event: MouseEvent | TouchEvent,
   ): void {
     this._reset();
     this.dropped.next({