UX: Fix TextColor value casing

[darkwing]

Explanation

Fixes casing of wrong TypeScript constant value

Pre-merge author checklist

• I've clearly explained:
  • What problem this PR is solving
  • How this problem was solved
  • How reviewers can test my changes
• Sufficient automated test coverage has been added

Pre-merge reviewer checklist

• Manual testing (e.g. pull and build branch, run in browser, test code being changed)
• PR is linked to the appropriate GitHub issue
• IF this PR fixes a bug in the release milestone, add this PR to the release milestone

If further QA is required (e.g. new feature, complex testing steps, large refactor), add the Extension QA Board label.

In this case, a QA Engineer approval will be be required.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[metamaskbot]

Builds ready [c26d900]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5
  • common: 0, 1, 2, 3, 4, 5
  • content-script: 0
  • contentscript: contentscript
  • disable-console: disable-console
  • inpage: inpage
  • policy-load: policy-load
  • sentry-install: sentry-install
  • ui: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1502 ± 44 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	99	172	124	17	8
		domContentLoaded	1378	1801	1502	91	44
		load	1378	1802	1502	91	44
		domInteractive	1378	1801	1502	91	44

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: -2 Bytes (-0.00%)
• common: 0 Bytes (0.00%)

[codecov]

Codecov Report

Merging #20133 (c26d900) into develop (e1722d7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop   #20133   +/-   ##
========================================
  Coverage    69.35%   69.35%           
========================================
  Files          986      986           
  Lines        37265    37265           
  Branches     10002    10002           
========================================
  Hits         25843    25843           
  Misses       11422    11422           

Impacted Files	Coverage Δ
...s/app/approve-content-card/approve-content-card.js	75.00% <ø> (ø)
...dger-instruction-field/ledger-instruction-field.js	58.90% <ø> (ø)