chore: Adjust plugin imports to only load metrics from the toolkit

[pan-kot]

Description

This is required for cloudscape-design/component-toolkit#190

The plugin code is updated to import metrics from /internal to /internal/metrics to not pull unneeded code in.

How has this been tested?

I tested that by installing this version of the toolkit: cloudscape-design/component-toolkit#190

Without change (all /internal deps is pulled in including react imports):

With change:

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 97.17%. Comparing base (6a5486b) to head (a194f72).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4213      +/-   ##
==========================================
+ Coverage   97.16%   97.17%   +0.01%     
==========================================
  Files         879      882       +3     
  Lines       25780    25826      +46     
  Branches     9328     9331       +3     
==========================================
+ Hits        25049    25097      +48     
+ Misses        725      723       -2     
  Partials        6        6              

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[pan-kot]

note: This change is technically not needed, but let's keep it.

It was a dependency of @size-limit/esbuild-why which I used to create the graphs.