wayland textinputv3: reset cursorRect when enableSurface

When enabling a surface(including entering a surface),
set_cursor_rectangle can be missing if the previous value
is the same as the current one.

Moved from 31762ec9b7ee9de84d85cb9be77c9f50a3c8d2e7

Done-by: lilydjwg li
Fixes: QTBUG-135341
Change-Id: I2356a24fcc44a71211b53a3a8c73192895a0de02
Reviewed-by: Liang Qi <liang.qi@qt.io>

src/plugins/platforms/wayland/qwaylandtextinputv3.cpp

@@ -54,6 +54,7 @@ void QWaylandTextInputv3::enableSurface(::wl_surface *surface)
     m_pendingCommitString.clear();
     m_pendingDeleteBeforeText = 0;
     m_pendingDeleteAfterText = 0;
+    m_cursorRect = QRect();
 
     enable();
     updateState(supportedQueries3, update_state_enter);