fix(module:timepicker): fix auto positioning picker

[KeelanS]

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: 6034

What is the new behavior?

The picker changes position depending on how much space there is.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[zorro-bot]

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[KeelanS]

I don't think tests are needed here. If they are, please guide me to another module that does test this because I have no idea how I would do this. :)

[codecov]

Codecov Report

Merging #6939 (df74033) into master (d392b2e) will not change coverage.
The diff coverage is n/a.

❗ Current head df74033 differs from pull request most recent head 02ddca2. Consider uploading reports for the commit 02ddca2 to get more accurate results

@@           Coverage Diff           @@
##           master    #6939   +/-   ##
=======================================
  Coverage   89.50%   89.50%           
=======================================
  Files         489      489           
  Lines       15805    15805           
  Branches     2428     2428           
=======================================
  Hits        14146    14146           
  Misses       1016     1016           
  Partials      643      643           

Impacted Files	Coverage Δ
components/time-picker/time-picker.component.ts	85.18% <ø> (ø)

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[simplejason]

LGTM

[simplejason]

fixed #6034