fix(module:modal): no longer trigger any action when closing

[maroon1]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

目前在关闭 Modal 的动画窗口期仍然能够触发 nzOnOK 或 nzOnCancel，造成用户意外的双击或者快速点击的情况下会重复的触发事件
Issue Number: N/A

What is the new behavior?

当 Modal 处于 Closing 状态下时，将忽略 nzOnOK 或 nzOnCancel 的事件

Does this PR introduce a breaking change?

[x] Yes
[ ] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[simplejason]

LGTM