Fix some crashes on widgets

app/src/main/java/org/isoron/uhabits/views/HabitScoreView.java

@@ -387,6 +387,7 @@ public class HabitScoreView extends ScrollableDataView implements HabitDataView
     {
         this.isTransparencyEnabled = enabled;
         createColors();
+        requestLayout();
     }
 
     private void setModeOrColor(Paint p, PorterDuffXfermode mode, int color)

app/src/main/res/layout/widget_graph.xml

@@ -43,7 +43,7 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:gravity="center"
-            android:textColor="?highContrastTextColor"/>
+            android:textColor="@color/white"/>
 
     </LinearLayout>