fix(module:modal): resolve memory leaks (#7123)

components/modal/modal-ref.ts

@@ -7,7 +7,7 @@ import { ESCAPE, hasModifierKey } from '@angular/cdk/keycodes';
 import { OverlayRef } from '@angular/cdk/overlay';
 import { EventEmitter } from '@angular/core';
 import { Subject } from 'rxjs';
-import { filter, take } from 'rxjs/operators';
+import { filter, take, takeUntil } from 'rxjs/operators';
 
 import { NzSafeAny } from 'ng-zorro-antd/core/types';
 import { isPromise } from 'ng-zorro-antd/core/util';
@@ -36,6 +36,8 @@ export class NzModalRef<T = NzSafeAny, R = NzSafeAny> implements NzModalLegacyAP
 
   private closeTimeout?: number;
 
+  private destroy$ = new Subject<void>();
+
   constructor(
     private overlayRef: OverlayRef,
     private config: ModalOptions,
@@ -64,7 +66,7 @@ export class NzModalRef<T = NzSafeAny, R = NzSafeAny> implements NzModalLegacyAP
         this._finishDialogClose();
       });
 
-    containerInstance.containerClick.pipe(take(1)).subscribe(() => {
+    containerInstance.containerClick.pipe(take(1), takeUntil(this.destroy$)).subscribe(() => {
       const cancelable = !this.config.nzCancelLoading && !this.config.nzOkLoading;
       if (cancelable) {
         this.trigger(NzTriggerAction.CANCEL);
@@ -88,9 +90,11 @@ export class NzModalRef<T = NzSafeAny, R = NzSafeAny> implements NzModalLegacyAP
         this.trigger(NzTriggerAction.CANCEL);
       });
 
-    containerInstance.cancelTriggered.subscribe(() => this.trigger(NzTriggerAction.CANCEL));
+    containerInstance.cancelTriggered
+      .pipe(takeUntil(this.destroy$))
+      .subscribe(() => this.trigger(NzTriggerAction.CANCEL));
 
-    containerInstance.okTriggered.subscribe(() => this.trigger(NzTriggerAction.OK));
+    containerInstance.okTriggered.pipe(takeUntil(this.destroy$)).subscribe(() => this.trigger(NzTriggerAction.OK));
 
     overlayRef.detachments().subscribe(() => {
       this.afterClose.next(this.result);
@@ -197,5 +201,6 @@ export class NzModalRef<T = NzSafeAny, R = NzSafeAny> implements NzModalLegacyAP
   _finishDialogClose(): void {
     this.state = NzModalState.CLOSED;
     this.overlayRef.dispose();
+    this.destroy$.next();
   }
 }