refactor(context menu): extract text alignment to theme property

[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 #2148 into master will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2148      +/-   ##
==========================================
+ Coverage   84.67%   84.71%   +0.03%     
==========================================
  Files         243      243              
  Lines        8478     8478              
  Branches      759      759              
==========================================
+ Hits         7179     7182       +3     
+ Misses       1076     1073       -3     
  Partials      223      223

Impacted Files	Coverage Δ
.../components/context-menu/context-menu.component.ts	100% <ø> (ø)	⬆️
...rc/framework/theme/components/menu/menu.service.ts	88.02% <0%> (+0.7%)	⬆️
.../framework/theme/components/menu/menu.component.ts	79.5% <0%> (+1.63%)	⬆️