refactor(colors): remove white and replace with semantic counterparts

[kathaypacific]

Description

This PR:

• remove Colors.white
• use "background" when white was used for background color styles
• use "textInverse" for any text that was set to white
• use "loadingSkeletonHighlight" for the skeleton loader

Test plan

N/a

Related issues

• Related to RET-1293

Backwards compatibility

Y

Network scalability

If a new NetworkId and/or Network are added in the future, the changes in this PR will:

• Continue to work without code changes, OR trigger a compilation error (guaranteeing we find it when a new network is added)

[codecov]

Codecov Report

Attention: Patch coverage is 96.15385% with 1 line in your changes missing coverage. Please review.

Project coverage is 89.11%. Comparing base (70f2708) to head (59f35f6).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/qrcode/QRTabBar.tsx	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6409      +/-   ##
==========================================
- Coverage   89.12%   89.11%   -0.01%     
==========================================
  Files         737      737              
  Lines       31876    31881       +5     
  Branches     5743     6052     +309     
==========================================
+ Hits        28408    28412       +4     
+ Misses       3421     3274     -147     
- Partials       47      195     +148     

Files with missing lines	Coverage Δ
src/account/ShakeForSupport.tsx	86.48% <ø> (ø)
src/backup/BackupIntroduction.tsx	90.00% <ø> (ø)
src/celoNews/CeloNewsFeedItem.tsx	100.00% <100.00%> (ø)
src/components/BottomSheetLegacy.tsx	95.74% <ø> (ø)
src/components/Button.tsx	100.00% <100.00%> (ø)
src/components/Card.tsx	100.00% <ø> (ø)
src/components/CircleButton.tsx	100.00% <100.00%> (ø)
src/components/ClipboardAwarePasteButton.tsx	78.26% <ø> (ø)
src/components/CodeRow.tsx	97.50% <ø> (ø)
src/components/Dropdown.tsx	100.00% <ø> (ø)
... and 68 more

... and 58 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 70f2708...59f35f6. Read the comment docs.

[jeanregisser]

🚀

[jeanregisser]

supernit: wondering if we should use skeletonPlaceholderHighlight?
Unless maybe we wanna add more things prefixed with loading?

[kathaypacific]

yes sorry it's not clear here but i will also create a color for the loading indicator, although the spinner doesn't have to be directly related to the skeleton loader. i can rename it!