[OTLP EXPORTER] Support setting byte arrays in all attribute collections and reject null keys

[dbarker]

Fixes # (issue)

Fixes a few non-compliant areas of the otlp attribute spec:

1. keys must not be null/empty
2. byte arrays must be supported by all attribute collections

See:

https://opentelemetry.io/docs/specs/otel/common/#attribute

https://opentelemetry.io/docs/specs/otel/common/#attribute-collections

The attribute key MUST be a non-null and non-empty string.
Case sensitivity of keys is preserved. Keys that differ in casing are treated as distinct keys.
The attribute value MUST be one of types defined in AnyValue.

All attribute collections then must accept a byte array.
Resources, Instrumentation Scopes, Metric points, Spans, Span Events, Span Links and Log Records, contain a collection of attributes.

Changes

• Reject empty keys when setting attributes
• Deprecate the PopulateAttribute/PopulateAnyValue methods that take allow_bytes boolean as a third arg.
• Add new PopulateAttribute/PopulateAnyValue overloads that accept a strongly typed AttributeValueLengthMax object as the third arg.
• Add tests for the new methods
• Update internal usage to use the new methods
• Behavior changes from v1.27
  • Attributes with empty keys are rejected
  • Byte sequences are now valid attribute values for instruments, spans, resources, and instrumentation scopes.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[dbarker]

Decided to deprecate these methods that take bool allow_bytes since allow_bytes is no longer needed, but we still need the max_length arg which will be new in version 1.28.

[dbarker]

These tests for duplicate attribute keys are added but disabled since OtlpRecordable will duplicate keys now.

[codecov]

Codecov Report

❌ Patch coverage is 92.25352% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.81%. Comparing base (46298b6) to head (135289a).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...xporters/otlp/src/otlp_populate_attribute_utils.cc	91.74%	10 Missing ⚠️
sdk/src/logs/multi_recordable.cc	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4226      +/-   ##
==========================================
+ Coverage   82.79%   82.81%   +0.03%     
==========================================
  Files         415      415              
  Lines       17452    17486      +34     
==========================================
+ Hits        14447    14480      +33     
- Misses       3005     3006       +1     

Files with missing lines	Coverage Δ
...try/exporters/otlp/otlp_populate_attribute_utils.h	100.00% <100.00%> (ø)
exporters/otlp/src/otlp_log_recordable.cc	38.97% <100.00%> (+0.81%)	⬆️
exporters/otlp/src/otlp_metric_utils.cc	91.98% <100.00%> (-0.04%)	⬇️
exporters/otlp/src/otlp_recordable.cc	90.36% <100.00%> (+0.09%)	⬆️
sdk/src/trace/span.cc	89.10% <100.00%> (+0.21%)	⬆️
sdk/src/logs/multi_recordable.cc	90.00% <50.00%> (-1.13%)	⬇️
...xporters/otlp/src/otlp_populate_attribute_utils.cc	92.74% <91.74%> (-0.02%)	⬇️

... and 1 file with indirect coverage changes

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