cubicweb #2091068 [cwconfig] fix gettext import [validation pending]

I was notified that in some circomstances, the "from gettext import translation" in cwconfig.py ~1168 imports the python standard gettext.py instead of the locally patched one.

"from cubicweb.gettext import translation" is said to fix the pb.

prioritynormal
typebug
done in3.13.10
load left0.000
closed by#241123f7bcd0 [cwconfig] absolute import (closes #2091068)