fix(button): Remove background-color from raised buttons on dark theme

[unascribed]

See: #819

This runs contrary to the guidelines, but considering MDC gives full control of button color through class names (and CSS is very flexible), it's likely a non-issue. This also fixes the text color being wrong when a light primary color is used.

Fair warning: I tested this by deleting the directive with Chrome devtools. I'm 90% sure my change here has the desired effect, but I haven't yet had a chance to test a fresh compile.

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[unascribed]

Signed.

[googlebot]

CLAs look good, thanks!

[codecov-io]

Codecov Report

Merging #833 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #833   +/-   ##
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  Coverage   99.93%   99.93%           
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  Files          68       68           
  Lines        3144     3144           
  Branches      387      387           
=======================================
  Hits         3142     3142           
  Misses          2        2

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[Garbee]

This runs contrary to the guidelines,

We should get input from the MD team on this then. As, what is currently provided is exactly what is specified here. The default's shouldn't go against that.

[unascribed]

I'd tend to agree, but I was (somewhat indirectly) asked to PR this by @traviskaufman on #819.

[Garbee]

I am not asking for a merge block. Simply a delay to get feedback from the design team on if this is appropriate. As what change is made by this PR is specifically against my entire understanding of the button component from when I made the original base for MCW.

If I were to comment on the issue with that, it could easily get lost/looked over. Best keep the discussions targeted on the issue/PR in question rather than spreading conversation out.

[amsheehan]

I won’t be available until Monday. @YiranM or @lynnjepsen, could you facilitate this?

[lynnmercier]

I apologize for not replying sooner, but I've found some time to look into this issue. I've written a longer explanation on the original issue and created a new PR to solve the original issue.

[amsheehan]

Closing, as @lynnjepsen seems to have confirmed what @Garbee and the spec says with design. Thanks again @unascribed, we really appreciate the effort, but in this case I think we're seeing a case that should be handled on an implementation level as regards color for mdc-button's on a dark theme.