fix(tabset): prevent select call if no active tab found

[yggg]

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• I read and followed the CONTRIBUTING.md guide.
• I read and followed the New Feature Checklist guide.

Short description of what this resolves:

[codecov]

Codecov Report

Merging #1444 into master will increase coverage by 0.25%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1444      +/-   ##
==========================================
+ Coverage   82.59%   82.84%   +0.25%     
==========================================
  Files         240      240              
  Lines        7320     7322       +2     
  Branches      656      655       -1     
==========================================
+ Hits         6046     6066      +20     
+ Misses       1085     1066      -19     
- Partials      189      190       +1

Impacted Files	Coverage Δ
...mework/theme/components/tabset/tabset.component.ts	92% <100%> (+37.83%)	⬆️