fix: checkmark icon missing after token import

[bergeron]

Description

After importing an erc20 token, the popup message was not rendering the checkmark icon.

The icon is from font-awesome, and their CSS works fine. But when we add @include design-system.H3, it overrode the font-family, breaking the icon.

Fixed by setting font size directly rather than bringing the whole H3.

Related issues

Manual testing steps

1. Import an erc20 token, either manually or via autodetection
2. Verify the green popup message has a checkmark icon

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I’ve followed MetaMask Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[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 [53a3e10]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-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, 6
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8
  • content-script: 0
  • ui: 0, 1, 10, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1510 ± 626 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	80	355	150	66	32
		domContentLoaded	11	78	28	17	8
		load	63	3137	1510	1303	626
		domInteractive	11	78	28	17	8

Bundle size diffs

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.56%. Comparing base (fef29be) to head (53a3e10).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop   #24005   +/-   ##
========================================
  Coverage    67.56%   67.56%           
========================================
  Files         1246     1246           
  Lines        48888    48888           
  Branches     12746    12746           
========================================
  Hits         33031    33031           
  Misses       15857    15857           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.