cubicweb-celery #10364472 test mode not set at least with CW 3.20 [validation pending]

Testing cwconfig.apphome is not enough, rather use cwconfig.mode

prioritynormal
typebug
done in0.1.0
load left0.000
closed by#b38332339907 Use the dedicated configuration attribute to determine if we are in test mode
patchUse the dedicated configuration attribute to determine if we are in test mode [applied]