chore: Remove old flashbar metrics

[just-boris]

Description

Unblock the build for this fix: cloudscape-design/component-toolkit#116

Related links, issue #, if available: n/a

How has this been tested?

No visual changes, PR build only will be enough

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?

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.45%. Comparing base (bcb11cb) to head (99cfb9c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3234      +/-   ##
==========================================
- Coverage   96.45%   96.45%   -0.01%     
==========================================
  Files         791      790       -1     
  Lines       22315    22299      -16     
  Branches     7667     7249     -418     
==========================================
- Hits        21524    21508      -16     
- Misses        739      784      +45     
+ Partials       52        7      -45     

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