cubicweb-elasticsearch #17077372 skip entity indexation on error rather than crashing [in-progress]

If an entity can't be indexed, it should not prevent other entities in the same transaction from being indeed.

prioritynormal
typebug
done in0.5.2
load0.000
load left0.000
closed by<not specified>
patch[ccplugin] do not crash if an entity failed to serialize [applied]