Add estimate_batch_distinct_count operation block passing support

What does this MR do?

Related to #332554 (closed).

This adds passing blocks to the metric instrumentation estimate_batch_distinct_count operation, to do some additional calculations on HLL buckets if necessary. This is the only missing feature to complete the support for this operation.

Unfortunately I don't have a metric example to go with this. Originally I wanted to include an example of usage_activity_by_stage.secure.*_pipelines metrics in !67915 (closed), but ultimately I closed the MR. Only two types of metrics use the estimate_batch_distinct_count method, and both of them are subject to change due to database ci_* tables decomposition.

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
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• [-] I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• [-] I have tested this MR in all supported browsers, or it's not needed.
• [-] I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.