Get rid of some clazy warnings in graphs2d/animation folder

Fix "c++11 range-loop might detach Qt container" warnings.

Change-Id: If43b44b56d5e096bb787285dfc8d28ec344ea149
Reviewed-by: Jere Tuliniemi <jere.tuliniemi@qt.io>
(cherry picked from commit c955907133)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 94e1fbd640)

src/graphs2d/animation/qgraphtransition.cpp

@@ -135,7 +135,7 @@ bool QGraphTransition::initialized()
 
 bool QGraphTransition::contains(QGraphAnimation::GraphAnimationType type)
 {
-    for (const auto anim : m_animations) {
+    for (const auto anim : std::as_const(m_animations)) {
         if (anim->animationType() == type)
             return true;
     }