Change color fn used to calculate icon colors for search typeahead

[joshuarrrr]

Description

Icons don't need to be as high contrast as text, so the 3:1 threshold of makeGraphicContrastColor is more appropriate

Issues Resolved

fixes #4628

Screenshot

These styles aren't actually currently used, because we don't have full typeahead support available in the query bar, except for historical queries. But I've manually updated some of the suggestions with the 4 color style classes affected by this change. The colors themselves haven't changed, but it fixes the error. Note that this change is only for the color variants - the contrast for the grayscale ones are probably worse, but defined elsewhere:

Testing the changes

Before:

np bld    log   [21:29:23.956] [info][@osd/optimizer] starting worker [1 bundle]
np bld    log   [21:29:27.418] [warning][@osd/optimizer] worker stderr WARNING: High enough contrast could not be determined. Most likely your background color does not adjust for dark mode.
np bld    log   [21:29:27.419] [warning][@osd/optimizer] worker stderr          on line 128:7 of node_modules/@elastic/eui/src/themes/eui-next/global_styling/functions/_colors.scss, in function `makeHighContrastColor`
np bld    log   [21:29:27.419] [warning][@osd/optimizer] worker stderr          from line 105:16 of src/plugins/data/public/ui/typeahead/_suggestion.scss
np bld    log   [21:29:27.419] [warning][@osd/optimizer] worker stderr          from line 1:9 of src/plugins/data/public/ui/typeahead/_index.scss
np bld    log   [21:29:27.419] [warning][@osd/optimizer] worker stderr          from line 2:9 of src/plugins/data/public/ui/_index.scss
np bld    log   [21:29:27.419] [warning][@osd/optimizer] worker stderr          from line 2:9 of src/plugins/data/public/index.scss
np bld    log   [21:29:27.419] [warning][@osd/optimizer] worker stderr 
np bld    log   [21:29:28.509] [warning][@osd/optimizer] worker stderr WARNING: High enough contrast could not be determined. Most likely your background color does not adjust for dark mode.
np bld    log   [21:29:28.509] [warning][@osd/optimizer] worker stderr          on line 128:7 of node_modules/@elastic/eui/src/themes/eui-next/global_styling/functions/_colors.scss, in function `makeHighContrastColor`
np bld    log   [21:29:28.509] [warning][@osd/optimizer] worker stderr          from line 105:16 of src/plugins/data/public/ui/typeahead/_suggestion.scss
np bld    log   [21:29:28.509] [warning][@osd/optimizer] worker stderr          from line 1:9 of src/plugins/data/public/ui/typeahead/_index.scss
np bld    log   [21:29:28.509] [warning][@osd/optimizer] worker stderr          from line 2:9 of src/plugins/data/public/ui/_index.scss
np bld    log   [21:29:28.510] [warning][@osd/optimizer] worker stderr          from line 2:9 of src/plugins/data/public/index.scss
np bld    log   [21:29:28.510] [warning][@osd/optimizer] worker stderr 
np bld    log   [21:29:32.591] [success][@osd/optimizer] 1 bundles compiled successfully after 10.2 sec, watching for changes

After:

np bld    log   [21:29:43.878] [success][@osd/optimizer] 1 bundles compiled successfully after 5.2 sec, watching for changes

Check List

• All tests pass
  • yarn test:jest
  • yarn test:jest_integration
  • yarn test:ftr
• New functionality includes testing.
• New functionality has been documented.
• Update CHANGELOG.md
• Commits are signed per the DCO using --signoff

[joshuarrrr]

This doesn't need a changelog entry - it's really just getting rid of a sass bundling warning.

[codecov]

Codecov Report

Merging #4884 (84b9709) into main (ce2d79e) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #4884      +/-   ##
==========================================
- Coverage   66.39%   66.39%   -0.01%     
==========================================
  Files        3396     3396              
  Lines       64801    64801              
  Branches    10359    10359              
==========================================
- Hits        43025    43023       -2     
- Misses      19217    19218       +1     
- Partials     2559     2560       +1     

Flag	Coverage Δ
Linux_1	34.85% <ø> (ø)
Linux_2	55.15% <ø> (ø)
Linux_3	44.23% <ø> (-0.01%)	⬇️
Linux_4	34.92% <ø> (ø)
Windows_1	34.87% <ø> (ø)
Windows_2	55.12% <ø> (ø)
Windows_3	44.23% <ø> (ø)
Windows_4	34.92% <ø> (ø)

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see 1 file with indirect coverage changes