Show colormap previews in menu

[rosteen]

This shows a preview of each colormap in the menu where you select them. Opening as draft since I'm iterating a bit more with @Jenneh. Currently looks like this:

I'm having an infuriating time trying to get the card element to center within the selection item, if anyone has ideas feel free to chime in.

[kecnry]

Here's one option to "center" by filling the full width

[rosteen]

@kecnry I implemented your suggestions for centering/filling the width, works well. Thanks!

I also talked to @Jenneh, she doesn't love the text-shadow (looks a little dated apparently) but thinks that being consistent with the layer tabs is more important than figuring out some other way of text outlining for now. Other than that I addressed her feedback by making the card flat and bolding the font.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.69%. Comparing base (50ebc1e) to head (cb18783).
Report is 180 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2900      +/-   ##
==========================================
- Coverage   88.70%   88.69%   -0.01%     
==========================================
  Files         111      111              
  Lines       17125    17122       -3     
==========================================
- Hits        15190    15187       -3     
  Misses       1935     1935              

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[javerbukh]

Looks good!

[rosteen]

Dev test failures are unrelated and I'll count @Jenneh as a second approval (we may revisit this and some related styling later but this is consistent with what exists). Merging.