fix(module:popconfirm): fix icon disappear when nzTitle is a TemplateRef instance

[WOOOFEI]

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?

Icon disappears when nzTitle is a TemplateRef instance.

Issue Number: N/A

What is the new behavior?

Icon won't disappear when nzTitle is a TemplateRef instance.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[codecov]

Codecov Report

Merging #2463 into next will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             next    #2463   +/-   ##
=======================================
  Coverage   95.84%   95.84%           
=======================================
  Files         487      487           
  Lines       12318    12318           
  Branches     1663     1663           
=======================================
  Hits        11806    11806           
  Misses        152      152           
  Partials      360      360

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[vthinkxie]

Hi @WOOOFEI ,
thanks for your pr
but this is not a bug, it provides the chance to rewrite the icon.

[WOOOFEI]

I'm handling with #2196, shall I add this change to that branch or just stay the same?

[wzhudev]

@WOOOFEI This would introduce breaking change. Maybe we should fix it later.