cubicweb #7170830 change_attribute_type migration command doesn't update live schema [validation pending]

which may lead to later error in a migration.

prioritynormal
typebug
done in3.21.2
load2.000
load left0.000
closed by#57c60a96de70 [migration] fix change_attribute_type to update the live schema
patch[migration] fix change_attribute_type to update the live schema [applied]