fix(module: carousel): fix set Carousel component selectedIndex invalid.

[Guoyuanqiang]

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-mobile/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: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[codecov]

Codecov Report

Merging #269 into master will decrease coverage by 0.12%.
The diff coverage is 81.81%.

@@            Coverage Diff            @@
##           master    #269      +/-   ##
=========================================
- Coverage   86.62%   86.5%   -0.13%     
=========================================
  Files         229     229              
  Lines        7367    7374       +7     
  Branches     1053    1053              
=========================================
- Hits         6382    6379       -3     
- Misses        568     584      +16     
+ Partials      417     411       -6

Impacted Files	Coverage Δ
components/carousel/carousel.component.ts	73.4% <81.81%> (-2.96%)	⬇️

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