feat(module:autocomplete,dropdown): add class & style properties in overlay panel

[cipchk]

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?

[ ] Bugfix
[x] 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: #2634

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[netlify]

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[codecov]

Codecov Report

Merging #2639 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2639      +/-   ##
==========================================
+ Coverage   95.61%   95.62%   +<.01%     
==========================================
  Files         495      495              
  Lines       12075    12079       +4     
  Branches     1687     1687              
==========================================
+ Hits        11546    11551       +5     
  Misses        169      169              
+ Partials      360      359       -1

Impacted Files	Coverage Δ
components/dropdown/nz-dropdown.component.ts	94.89% <100%> (+0.1%)	⬆️
...ponents/auto-complete/nz-autocomplete.component.ts	96.47% <100%> (+0.08%)	⬆️
components/tabs/nz-tabset.component.ts	97.43% <0%> (+0.85%)	⬆️

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