Polish menu before creating platform window

A style may want to change the surface format of the window. Changing the
surface format after the window has been created has no effect though.
One example of this is Breeze where the context menus created here had an
ugly border instead of the intended look. This is because the setting of
Qt::WA_TranslucentBackground by breeze had no effect anymore after the
window was already created.
1 job for !189 with work/polishedmenu in 41 minutes and 23 seconds (queued for 41 minutes and 41 seconds)
detached
Status Job ID Name Coverage
  Build
failed #75718
linux kf5-qt5 qt5.12

00:41:23

45.0%
 
Name Stage Failure
failed
linux kf5-qt5 qt5.12 Build
build: found 16392 matching files and directories  
WARNING: Uploading artifacts as "archive" to coordinator... failed id=75718 responseStatus=502 Bad Gateway status=502 token=SqxFk_xz
WARNING: Retrying... context=artifacts-uploader error=invalid argument
WARNING: Uploading artifacts as "archive" to coordinator... failed id=75718 responseStatus=502 Bad Gateway status=502 token=SqxFk_xz
WARNING: Retrying... context=artifacts-uploader error=invalid argument
WARNING: Uploading artifacts as "archive" to coordinator... failed id=75718 responseStatus=502 Bad Gateway status=502 token=SqxFk_xz
FATAL: invalid argument
Cleaning up file based variables
ERROR: Job failed: exit code 1