fix(module:tabs): index only changed by router event when nzLinkRouter

[yangjunhan]

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: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #6293 (6468b5c) into master (0694079) will increase coverage by 0.08%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master    #6293      +/-   ##
==========================================
+ Coverage   89.80%   89.89%   +0.08%     
==========================================
  Files         477      478       +1     
  Lines       15186    15245      +59     
  Branches     2298     2316      +18     
==========================================
+ Hits        13638    13704      +66     
+ Misses        949      930      -19     
- Partials      599      611      +12     

Impacted Files	Coverage Δ
components/tabs/tab-link.directive.ts	42.85% <0.00%> (-7.15%)	⬇️
components/tabs/tabset.component.ts	89.47% <75.00%> (+5.68%)	⬆️
components/core/services/scroll.ts	81.96% <0.00%> (-1.64%)	⬇️
components/modal/modal-container.ts	92.30% <0.00%> (-0.80%)	⬇️
components/collapse/collapse.module.ts	100.00% <0.00%> (ø)
components/image/utils.ts	89.65% <0.00%> (ø)
components/collapse/collapse-panel.component.ts	93.10% <0.00%> (+0.24%)	⬆️
components/tabs/tab-nav-bar.component.ts	83.09% <0.00%> (+0.70%)	⬆️
components/image/image-preview.component.ts	90.13% <0.00%> (+2.27%)	⬆️
components/tabs/tabs-ink-bar.directive.ts	87.09% <0.00%> (+3.22%)	⬆️
... and 3 more

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