cubicweb #5362574 RecomputeAttributeOperation crash on postgresql [validation pending]

RecomputeAttributeOperation transforms the attribute formula to do its update, but it breaks if the formula uses an aggregate function because it needs a GROUPBY X.

Noticed when trying to run unittest_migractions on postgresql.

prioritynormal
typebug
done in3.20.8
load0.250
load left0.000
closed by#7e311ee8b5b0 [hooks] manhandle the parsed rql query, not its string representation
patch[hooks] manhandle the parsed rql query, not its string representation [applied]