set distinct UI name for override_desktop_mode_features toggle

Both override_desktop_mode_features and enable_freeform_support toggle had the same name UI name:
"Enable freeform windows".

Author: muhomorr

res/xml/development_settings.xml

@@ -750,7 +750,7 @@
 
         <SwitchPreferenceCompat
             android:key="override_desktop_mode_features"
-            android:title="@string/enable_desktop_mode" />
+            android:title="Enable desktop mode support" />
 
         <SwitchPreferenceCompat
             android:key="enable_freeform_support"