[METRICS SDK] Validate Base2 Exponential Histogram Aggregation config

[RaviTriv]

Fixes #4250

Changes

Validates the Base2 Exponential Histogram Aggregation parameters to align with the OTEL configuration spec.

Naming and Types

• Updated Base2ExponentialHistogramAggregationConfig::max_buckets_ to max_size_
• Set Base2ExponentialBucketHistogramAggregationConfiguration::max_scale type to int32
  • Added DocumentNode::GetSignedInteger to handle negative values

Validation

• Throw InvalidSchemaException if config value is out of range.
• Log warning and set to default value.
• Updated defaults to align with the spec.

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

[codecov]

Codecov Report

❌ Patch coverage is 85.41667% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.17%. Comparing base (c4af827) to head (9c689b9).

Files with missing lines	Patch %	Lines
sdk/src/configuration/document_node.cc	63.64%	4 Missing ⚠️
sdk/src/configuration/sdk_builder.cc	0.00%	2 Missing ⚠️
sdk/src/configuration/ryml_document_node.cc	90.91%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4253      +/-   ##
==========================================
+ Coverage   78.15%   78.17%   +0.03%     
==========================================
  Files         440      440              
  Lines       18741    18781      +40     
==========================================
+ Hits        14645    14681      +36     
- Misses       4096     4100       +4     

Files with missing lines	Coverage Δ
...ntial_bucket_histogram_aggregation_configuration.h	0.00% <ø> (ø)
...de/opentelemetry/sdk/configuration/document_node.h	100.00% <ø> (ø)
...entelemetry/sdk/configuration/ryml_document_node.h	100.00% <ø> (ø)
...metry/sdk/metrics/aggregation/aggregation_config.h	100.00% <ø> (ø)
...entelemetry/sdk/metrics/exemplar/reservoir_utils.h	100.00% <100.00%> (ø)
sdk/src/configuration/configuration_parser.cc	78.30% <100.00%> (+0.24%)	⬆️
...egation/base2_exponential_histogram_aggregation.cc	96.74% <100.00%> (+0.12%)	⬆️
sdk/src/configuration/ryml_document_node.cc	80.40% <90.91%> (+0.49%)	⬆️
sdk/src/configuration/sdk_builder.cc	5.00% <0.00%> (ø)
sdk/src/configuration/document_node.cc	77.85% <63.64%> (-1.06%)	⬇️

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