uic: Add #ifdef depending on Qt version for QPalette::Accent

Complements 17c589df94.

Fixes: QTBUG-133651
Change-Id: Ieb57df30863f8493cd170d80220ae09177842ede
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>
(cherry picked from commit 1832ac4d25dd5c32963c47ad38836a0ea2ebd793)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 20646e132c04f2e181db354b89cc42b70ede47ad)

src/tools/uic/cpp/cppwriteinitialization.cpp

@@ -2039,6 +2039,8 @@ static inline QVersionNumber colorRoleVersionAdded(const QString &roleName)
 {
     if (roleName == "PlaceholderText"_L1)
         return {5, 12, 0};
+    if (roleName == "Accent"_L1)
+        return {6, 6, 0};
     return {};
 }