[PlasmaComponents Menu] Set WA_TranslucentBackground on the underlying QMenu

Authored by broulik on Nov 24 2017, 9:40 AM.

Description

[PlasmaComponents Menu] Set WA_TranslucentBackground on the underlying QMenu

This ensures the menu can have nice round corners with Breeze and Oxygen. The same had already been done in ContainmentInterface's menu.

CHANGELOG: Fixed an issue where PlasmaComponents Menu would appear with broken corners

CCBUG: 381799

Differential Revision: https://phabricator.kde.org/D8965