Utils: Introduce a convenience function creatorColor()

... forwarding to creatorTheme()->color(...)

Change-Id: Iefaa043495127b3e500ed225584481d3ec0f8c1f
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/debugger/watchhandler.cpp

@@ -978,7 +978,7 @@ static QColor valueColor(const WatchItem *item, int column)
                 color = Theme::Debugger_WatchItem_ValueChanged;
         }
     }
-    return creatorTheme()->color(color);
+    return creatorColor(color);
 }
 
 static DisplayFormats typeFormatList(const WatchItem *item)