fix: dropdown and autocomplete animations

[yangjunhan]

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?

Issue Number: #6018

What is the new behavior?

Dropdown has open animation every time which triggers it. Autocompletion has close animation after clicking outside the input.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[codecov]

Codecov Report

Merging #6143 (6d2249c) into master (ddc7ded) will increase coverage by 0.00%.
The diff coverage is 95.45%.

❗ Current head 6d2249c differs from pull request most recent head 93713e4. Consider uploading reports for the commit 93713e4 to get more accurate results

@@           Coverage Diff           @@
##           master    #6143   +/-   ##
=======================================
  Coverage   89.90%   89.90%           
=======================================
  Files         479      479           
  Lines       15319    15338   +19     
  Branches     2333     2338    +5     
=======================================
+ Hits        13772    13790   +18     
  Misses        930      930           
- Partials      617      618    +1     

Impacted Files	Coverage Δ
components/dropdown/dropdown.directive.ts	88.57% <85.71%> (-0.21%)	⬇️
...ts/auto-complete/autocomplete-trigger.directive.ts	95.83% <100.00%> (+0.15%)	⬆️
components/auto-complete/autocomplete.component.ts	91.58% <100.00%> (+0.24%)	⬆️
components/dropdown/dropdown-menu.component.ts	85.29% <100.00%> (+1.42%)	⬆️

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[vthinkxie]

Hi, there are some conflicts that need to be resolved, could you rebase onto master? thanks