cubicweb #3564510 changed error message for sqlite unique constraint violations [validation pending]

Recent (3.8.x?) sqlite versions have a different error message. since we parse that message to turn it into a UniqueTogetherError, we need to adjust.

prioritynormal
typetask
done in3.19.0
load0.500
load left0.000
closed by#079b5279a2cd [server] Handle unique constraint violations under recent sqlite, #a0cf2993b6d3 [server] Handle unique constraint violations under recent sqlite
patch[server] Handle unique constraint violations under recent sqlite [applied][server] On constraint violation handling, clean the trailing _idx in index names. [folded][server] Handle unique constraint violations under recent sqlite [applied]