[shared] Remove TagTransformer and improve TagWriter

[CodeBlanch]

Follow-up to #5476 Relates to #5475

Changes

• Removes TagTransformer as everything is now using TagWriter
• Converts JsonStringArray tests to use TagWriter and fix bugs that manifested
• Uses ReadOnlySpan<char> for strings in TagWriter to make it possible to bypass allocations when writing chars orstrings which get trimmed due to length limits

Merge requirement checklist

• [X] CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• [X] Unit tests added/updated

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 85.69%. Comparing base (6250307) to head (f2adebc). Report is 223 commits behind head on main.

:exclamation: Current head f2adebc differs from pull request most recent head eb86a50. Consider uploading reports for the commit eb86a50 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5602      +/-   ##
==========================================
+ Coverage   83.38%   85.69%   +2.30%     
==========================================
  Files         297      254      -43     
  Lines       12531    10979    -1552     
==========================================
- Hits        10449     9408    -1041     
+ Misses       2082     1571     -511     

Flag	Coverage Δ
unittests	?
unittests-Solution-Experimental	85.64% <66.66%> (?)
unittests-Solution-Stable	85.65% <66.66%> (?)
unittests-Unstable-Core	19.91% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...nTelemetryProtocol/Implementation/OtlpTagWriter.cs	100.00% <100.00%> (ø)
....Exporter.Zipkin/Implementation/ZipkinTagWriter.cs	63.63% <ø> (ø)
...xporter.Console/Implementation/ConsoleTagWriter.cs	11.53% <0.00%> (ø)

... and 112 files with indirect coverage changes