Draft: ActionButton: Fix detection of action under mouse in RTL
Note: Draft because needs to be retargeted and tested on KF6 (master) first.
ActionButton: Fix and improve test
Setting header manually doesn't seem to be well-supported, and triggers various errors in runtime.
ActionButton: Fix reference to a tooltip attached property
Didn't work, triggered a warning that ToolTip should be attached to a QQuickItem.
ActionButton: Reset actionUnderMouse when not containing mouse
ActionButton: Port from global layoutDirection to LayoutMirroring
It allows more granular control over mirroring, which otherwise in most situations would be set on the top level window and inherited.
ActionButton: Fix detection of action under mouse in RTL
Less hard to validate math, simpler code, correct RTL behavior.