Return early if close button accepts input event

Summary:
Otherwise we close the effect whenever the close is pressed which is a
behavioural change.

That in turn leads to bigger bugs

BUG: 415155

Test Plan:
Ran effect
Clicked on the "Whitespace" of the dash
Clicked on the close

Now matches desktopgrid code

Reviewers: #kwin, zzag, ngraham

Reviewed By: #kwin, zzag, ngraham

Subscribers: ngraham, zzag, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D27333

effects/presentwindows/presentwindows.cpp

@@ -538,6 +538,7 @@ void PresentWindowsEffect::windowInputMouseEvent(QEvent *e)
     if (!me) {
         return;
     }
+    me->setAccepted(false);
     if (m_closeView) {
         const bool contains = m_closeView->geometry().contains(me->pos());
         if (!m_closeView->isVisible() && contains) {
@@ -545,6 +546,9 @@ void PresentWindowsEffect::windowInputMouseEvent(QEvent *e)
         }
         m_closeView->forwardMouseEvent(e);
     }
+    if (e->isAccepted()) {
+        return;
+    }
     inputEventUpdate(me->pos(), me->type(), me->button());
 }