feat: Add labels for folder/object icons in S3 resource selector

[avinashbot]

Waiting for translations to come back. Will merge them separately before rebasing this branch and adding support for them.

Description

These meaningful icons in the S3 resource selector aren't labelled. Whoops. So this PR adds labelIconFile and labelIconFolder properties to the component's I18nStrings interface.

Related links, issue #, if available: AWSUI-60208

How has this been tested?

Unit tests.

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.44%. Comparing base (f8a00dd) to head (c7c9405).
Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #3248    +/-   ##
========================================
  Coverage   96.44%   96.44%            
========================================
  Files         791      791            
  Lines       22568    22569     +1     
  Branches     7385     7802   +417     
========================================
+ Hits        21765    21766     +1     
+ Misses        796      750    -46     
- Partials        7       53    +46     

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