Replace FIXME for flags value in ExponentialHistogram aggregation

[chimchim89]

Description

Replaces the two FIXME: Find the right value for flags comments in _ExponentialBucketHistogramAggregation.collect() in opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/aggregation.py.

Per the OpenTelemetry proto spec, flags is a bitmask where 0 means no flags are set. The only other defined value is DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK = 1, which represents a no-recorded-value condition. These code paths are only reached when a recorded value exists, so flags=0` is correct. The comments have been updated to explain this.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

This change only updates comments, no logic was changed. Verified with:

• tox -e lint
• tox -e precommit

Does This PR Require a Contrib Repo Change?

• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[herin049]

I would want to wait to resolve this comment until #4916 is merged in.

[chimchim89]

I would want to wait to resolve this comment until #4916 is merged in.

thanks! I'll wait for #4916 to be merged and then update this PR accordingly.