fix(menu): clear typing for NbMenuItem pathMatch property

[bram-pkg]

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:

It helps with autocompletion and helping the developer list all possible options.

[codecov]

Codecov Report

Merging #1627 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1627   +/-   ##
=======================================
  Coverage   83.88%   83.88%           
=======================================
  Files         232      232           
  Lines        7595     7595           
  Branches      670      670           
=======================================
  Hits         6371     6371           
  Misses       1026     1026           
  Partials      198      198

Impacted Files	Coverage Δ
...rc/framework/theme/components/menu/menu.service.ts	87.32% <100%> (ø)	⬆️

[yggg]

Thanks for contribution @BramCeulemans