Instead of doing this directly inside the PE_FrameLineEdit as this can
be used directly when a stylesheet is set the rect of the lineedit used
in the combobox in fusion style is filled directly with the base brush.
This ensures it still renders the background correctly when using fusion
style, but enables stylesheets to work as it will not override that if
the background is set in a stylesheet for a combobox.
Fixes: QTBUG-75816
Change-Id: I50a0600b500088ebcf1d70a02f9c74c6040d34d9
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
81b33a8252