Instrument offsets in API pagination

What does this MR do?

This adds histogram metric to get more insight into the offset-based API pagination. We are interested in understanding user behavior because we anticipate we want to deprecate offset-based pagination for high offsets soon. See #34011 (closed).

Instrumentation can be enabled with feature flag pagination_offset_metrics. It's disabled by default.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry