No Bug: Fix for console warning about `leo.nft` symbol size

[StephenHeaps]

Summary of Changes

Opening NFT tab can log a few console warnings about leo.nft symbol, for example:

[SwiftUI] No image named 'leo.nft' found in asset catalog for /Users/stephenheaps/Library/Developer/CoreSimulator/Devices/B85864FA-AD05-49A0-A247-146C5D39394F/data/Containers/Bundle/Application/DC7A00C9-BB00-40BB-BB16-7FD7459F9A25/Client.app/Brave_DesignSystem.bundle
[framework] CoreUI: -[CUICatalog namedVectorGlyphWithName:scaleFactor:deviceIdiom:layoutDirection:glyphSize:glyphWeight:glyphPointSize:appearanceName:] 'leo.nft' called with scaleFactor == 2.000000 glyphPointSize == 0.000000 at '/Users/stephenheaps/Library/Developer/CoreSimulator/Devices/B85864FA-AD05-49A

This pull request fixes #

Submitter Checklist:

• [x] Unit Tests are updated to cover new or changed functionality
• [x] User-facing strings use NSLocalizableString()
• [x] New or updated UI has been tested across:
  • [x] Light & dark mode
  • [x] Different size classes (iPhone, landscape, iPad)
  • [x] Different dynamic type sizes

Test Plan:

1. Open NFT tab on any device with debugger attached, filter by leo.nft.
2. Verify no more logs/warnings about leo.nft symbol

Screenshots:

Reviewer Checklist:

• [ ] Issues include necessary QA labels:
  • QA/(Yes|No)
  • bug / enhancement
• [ ] Necessary security reviews have taken place.
• [ ] Adequate unit test coverage exists to prevent regressions.
• [ ] Adequate test plan exists for QA to validate (if applicable).
• [ ] Issue and pull request is assigned to a milestone (should happen at merge time).