feat(dialog): Integrate with MDC List; add keyboard action handling

[kfranqueiro]

Fixes #3592.

Also adds a couple of tests for autoStackButtons that I apparently missed before.

[williamernest]

LGTM.

[codecov-io]

Codecov Report

Merging #3594 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3594      +/-   ##
==========================================
+ Coverage   98.35%   98.43%   +0.07%     
==========================================
  Files         120      120              
  Lines        5176     5182       +6     
  Branches      643      645       +2     
==========================================
+ Hits         5091     5101      +10     
+ Misses         85       81       -4

Impacted Files	Coverage Δ
packages/mdc-dialog/index.js	100% <100%> (+4.39%)	⬆️
packages/mdc-dialog/foundation.js	100% <100%> (ø)	⬆️

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