Convert OtelRumConfig to kotlin

[fractalwrench]

Goal

Converts OtelRumConfig to Kotlin. I've attempted to maintain API backwards compatibility with this change as much as possible & there shouldn't be a change in the API dump other than the addition of the final modifier.

[fractalwrench]

I deleted this test case (and the ability to pass null attributes) as keeping it would mean that getGlobalAttributesSupplier() would need to invoke the supplier, check whether the value was null, and then return the supplier again. I assumed removing the ability to pass null was preferable but don't have strong opinions if others disagree

[codecov]

Codecov Report

❌ Patch coverage is 82.35294% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.00%. Comparing base (869e348) to head (206bfd2).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...a/io/opentelemetry/android/config/OtelRumConfig.kt	82.35%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1356      +/-   ##
==========================================
- Coverage   64.02%   64.00%   -0.02%     
==========================================
  Files         157      157              
  Lines        3099     3098       -1     
  Branches      318      318              
==========================================
- Hits         1984     1983       -1     
  Misses       1022     1022              
  Partials       93       93              

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[LikeTheSalad]

LGTM. Cheers 👍