cubicweb #9133268 temporary svg files not deleted [validation pending]

the schemagraph view as rewritten for #3400448 does not delete its temporary files.

prioritynormal
typebug
done in3.20.12
load0.250
load left0.000
closed by#894c14f08380 [web/views] unlink svg temp file after we're done
patch[web/views] unlink svg temp file after we're done [applied]