HogQL: Support for distinct aggregate functions like countDistinctIf

[thmsobrmlr]

Is your feature request related to a problem?

This doesn't work in HogQL, but works in ClickHouse:

SELECT sumDistinct(x) FROM (SELECT number % 13 AS x FROM numbers(1000))

Describe the solution you'd like

Implement the -Distinct combinator for aggregate functions ClickHouse/ClickHouse#10930 / expose these ClickHouse functions.

Describe alternatives you've considered

Use the aggregateFn(DISTINCT ...) syntax:

SELECT sum(DISTINCT x) FROM (SELECT number % 13 AS x FROM numbers(1000))

Additional context

ClickHouse/ClickHouse#11517 (comment)