[rql2sql] fix handling of the ORDERBY clause when the aggregation function is "embedded"
ie. a situation like:
Any X GROUPBY X ORDERBY COUNT(Y) WHERE ...
works fine since the aggregation function (COUNT) if the first one, whereas a situation like the proposed test:
Any X GROUPBY X ORDERBY ABS(COUNT(Y)) WHERE ...
failed due to the fact we only checked the top aggratation function (ABS).
Closes #17108671