cubicweb-celerytask #15799231 Progress bar refresh task does not always emit the statechanged event [validation pending]

When the task state changes between the server-side html generation and the first ajax request, the statechanged event is not emitted. This is especially inconvenient for very short tasks or quick failures.

prioritynormal
typebug
done in0.2.0
load left0.000
closed by#0e994950c46d Use the same initial state server- and client-side in the progress bar
patchUse the same initial state server- and client-side in the progress bar [applied]