[9.1] Fixes esql class cast bug in STATS at planning level (#137511)

[ncordon]

Backport

This will backport the following commits from main to 9.1 #137511

Description

Addresses #133992 and #136598, partially.

Missing from this pr that we still need to do: at the moment the runtime part tries to avoid double computations, resulting in exceptions if the plan is correct but not optimal. In other words, queries like:

from airports 
rename scalerank AS x 
stats  a = count(x), b = count(x) + count(x), c = count_distinct(x)

should had never failed at runtime even if the plan was not optimal for repeated aggregations.

[astefan]

LGTM