fix(sidebar): emit state change

[yggg]

Please read and mark the following check list before creating a pull request:

• 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 #2645 (03ac2bd) into master (d10275b) will decrease coverage by 1.61%.
The diff coverage is 26.19%.

@@            Coverage Diff             @@
##           master    #2645      +/-   ##
==========================================
- Coverage   79.09%   77.48%   -1.62%     
==========================================
  Files         258      262       +4     
  Lines        7966     8216     +250     
  Branches      872      894      +22     
==========================================
+ Hits         6301     6366      +65     
- Misses       1391     1576     +185     
  Partials      274      274              

Impacted Files	Coverage Δ
...mework/theme/components/select/select.component.ts	86.82% <0.00%> (ø)
...amework/theme/components/tag/tag-list.component.ts	19.70% <19.70%> (ø)
...mework/theme/components/tag/tag-input.directive.ts	25.00% <25.00%> (ø)
...rc/framework/theme/components/tag/tag.component.ts	32.14% <32.14%> (ø)
.../components/autocomplete/autocomplete.directive.ts	83.12% <100.00%> (+0.10%)	⬆️
...work/theme/components/sidebar/sidebar.component.ts	58.27% <100.00%> (+0.92%)	⬆️
src/framework/theme/components/tag/tag.module.ts	100.00% <100.00%> (ø)
... and 1 more