[effects/wobblywindows] Fix visual artifacts caused by maximize effect

Summary:
If one wants to drag a maximized window while he or she has enabled both
the Wobbly Windows and the Maximize effect, visual artifacts can be
shown.

When the Maximize effect animates transition from maximize to restore,
some parts of the window can overshoot repaint regions(because of
wobbliness), leaving us with the visual artifacts.

To fix that, we have to take into account current scale and translation
when calculating dirty region in the Wobbly Windows effect.

BUG: 370612
FIXED-IN: 5.14.1

Test Plan: When dragging maximized windows, there are no visual artifacts anymore.

Reviewers: KWin, davidedmundson

Reviewed By: KWin, davidedmundson

Subscribers: abetts, kwin

Tags: KWin

Differential Revision: https://phabricator.kde.org/D15961