[ToolTip] Stop show timer if hideTooltip is called

This prevents the tooltip from showing up if hideTooltip was called
before it was shown.

BUG: 358894

Differential Revision: https://phabricator.kde.org/D959

src/declarativeimports/core/tooltip.cpp

@@ -255,6 +255,7 @@ void ToolTip::setInteractive(bool interactive)
 
 void ToolTip::hideToolTip()
 {
+    m_showTimer->stop();
     tooltipDialogInstance()->dismiss();
 }