fix(opentelemetry-core): validate "ot" entry and defer tracestate vaidation

[david-luna]

Which problem is this PR solving?

Fixes #790 and also adds validation of the ot entry according to the spec. Without this validation we could end up with an invalid ot entry in tracestate.

Short description of the changes

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Unit tests

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added

[codecov]

Codecov Report

❌ Patch coverage is 94.54545% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.54%. Comparing base (dcbead5) to head (37d0813).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...ackages/opentelemetry-core/src/trace/TraceState.ts	94.54%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6459      +/-   ##
==========================================
- Coverage   95.68%   94.54%   -1.15%     
==========================================
  Files         364      267      -97     
  Lines       11786     7475    -4311     
  Branches     2744     1565    -1179     
==========================================
- Hits        11278     7067    -4211     
+ Misses        508      408     -100     

Files with missing lines	Coverage Δ
api/src/trace/internal/tracestate-impl.ts	100.00% <ø> (ø)
api/src/trace/internal/utils.ts	100.00% <ø> (ø)
...ackages/opentelemetry-core/src/trace/TraceState.ts	95.31% <94.54%> (-4.69%)	⬇️

... and 109 files with indirect coverage changes

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