[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
• In PopulateAttribute/PopulateAnyValue methods parameters:
  • remove allow_bytes
  • add a strongly typed AttributeValueLengthMax object
• Add tests for the modified methods
• Update internal usage to use the new parameters
• Behavior changes from v1.28
  • 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]

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

[codecov]

Codecov Report

❌ Patch coverage is 96.62162% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.19%. Comparing base (b1d403d) to head (d0543f7).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...xporters/otlp/src/otlp_populate_attribute_utils.cc	98.25%	2 Missing ⚠️
...include/opentelemetry/sdk/common/attribute_utils.h	77.78%	2 Missing ⚠️
sdk/src/logs/multi_recordable.cc	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4226      +/-   ##
==========================================
+ Coverage   81.16%   81.19%   +0.03%     
==========================================
  Files         444      444              
  Lines       18800    18880      +80     
==========================================
+ Hits        15258    15328      +70     
- Misses       3542     3552      +10     

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	39.75% <100.00%> (+1.59%)	⬆️
exporters/otlp/src/otlp_metric_utils.cc	91.98% <100.00%> (-0.04%)	⬇️
exporters/otlp/src/otlp_recordable.cc	91.27% <100.00%> (+0.15%)	⬆️
sdk/src/trace/span.cc	93.70% <100.00%> (+0.12%)	⬆️
sdk/src/logs/multi_recordable.cc	90.00% <50.00%> (-1.13%)	⬇️
...xporters/otlp/src/otlp_populate_attribute_utils.cc	96.99% <98.25%> (+4.23%)	⬆️
...include/opentelemetry/sdk/common/attribute_utils.h	95.63% <77.78%> (+0.21%)	⬆️

... and 2 files with indirect coverage changes

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[dbarker]

Hi @owent Thanks for initial feedback. Can you take another review pass?

[owent]

There's still an unnecessary conversion, but it's harmless. The rest LGTM. Thanks.

[marcalff]

do-not-merge label: to merge after the release of opentelemetry-cpp 1.28.0

[marcalff]

LGTM, thanks for the fix.