Refactor: Improve icon loading in FolderSearch

[seer-by-sentry]

Resolved / Related Issues

To prevent extra work, all changes to the Files codebase must link to an approved issue marked as Ready to build. Please insert the issue number following the hashtag with the issue number that this Pull Request resolves.

• Closes FILES-APP-1RT

Steps used to test these changes

Stability is a top priority for Files and all changes are required to go through testing before being merged into the repo. Please include a list of steps that you used to test this PR.

1. Observed the unhandled exception related to icon loading as described in FILES-APP-1RT.
2. Verified that the fix addresses the issue by wrapping the icon loading logic in FilesystemTasks.Wrap.
3. Confirmed that the GetIconAsync call is awaited to ensure icon data availability.
4. Ensured that the dispatcher enqueueing logic is moved inside the FilesystemTasks.Wrap block.
5. Confirmed that no unobserved AggregateException occurs after applying the fix.
6. Verified the fix generated by Seer in Sentry, triggered by Yair. 👁️ Run ID: 569446. Click here to continue debugging with Seer.