fix(menu): recompute index before marking selection

[lasalvavida]

Fixed issues with changing menu contents in menus with selectable items. Marking selected items in a menu is deferred until the menu closes, so if the menu contents change before the callback is executed, the wrong item can be marked in the DOM.

[codecov-io]

Codecov Report

Merging #5047 into master will increase coverage by 0.29%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #5047      +/-   ##
==========================================
+ Coverage   98.79%   99.09%   +0.29%     
==========================================
  Files         122      122              
  Lines        5830     5831       +1     
  Branches      763      763              
==========================================
+ Hits         5760     5778      +18     
+ Misses         69       52      -17     
  Partials        1        1

Impacted Files	Coverage Δ
packages/mdc-menu/foundation.ts	96.29% <100%> (+0.04%)	⬆️
packages/mdc-checkbox/component.ts	96.87% <0%> (+1.04%)	⬆️
packages/mdc-tab/component.ts	98.36% <0%> (+3.27%)	⬆️
packages/mdc-base/component.ts	100% <0%> (+3.57%)	⬆️
packages/mdc-ripple/component.ts	100% <0%> (+3.77%)	⬆️
packages/mdc-auto-init/index.ts	100% <0%> (+4.16%)	⬆️
packages/mdc-ripple/util.ts	97.56% <0%> (+4.87%)	⬆️
packages/mdc-switch/component.ts	98.27% <0%> (+6.89%)	⬆️
packages/mdc-radio/component.ts	95.83% <0%> (+8.33%)	⬆️

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[abhiomkar]

Thanks for the pull request!

[abhiomkar]

LGTM, need a unit test test/unit/mdc-menu/mdc-menu.test.js (Preferably without mocks).

[abhiomkar]

LGTM.