Remove "AND" operator - postgres_hll and redis_hll

What does this MR do and why?

We want to remove an unused feature. See #440599 (closed) for context.

The plan is to remove the feature entirely in a few steps to make reviews easier:

1. Remove usage of the Intersection class from all sources postgres_hll and redis_hll. (This MR)
2. Remove the Intersection class and support for using the AND operator
3. Remove all usage of the operator property in the code
4. Update generator to output metric definitions without operator. (Requires that operator becomes optional in the json schema)
5. Migrate remove operator from all (currently 77) aggregated metric definitions
6. Update json schema do disallow the operator property

MR acceptance checklist

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Related to #440599 (closed)