feat(module:collapse): support nzExpandIconPosition

[vthinkxie]

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
[ ] 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: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #4781 into master will decrease coverage by 0.02%.
The diff coverage is 77.77%.

@@            Coverage Diff            @@
##           master   #4781      +/-   ##
=========================================
- Coverage   93.22%   93.2%   -0.03%     
=========================================
  Files         505     505              
  Lines       12729   12742      +13     
  Branches     1955    1955              
=========================================
+ Hits        11867   11876       +9     
- Misses        451     455       +4     
  Partials      411     411

Impacted Files	Coverage Δ
components/collapse/collapse.module.ts	100% <ø> (ø)
components/collapse/collapse-panel.component.ts	92.85% <71.42%> (ø)
components/collapse/collapse.component.ts	93.1% <81.81%> (ø)

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