Android: Set preferMinimalPostProcessing="true"

When using the combination of Android 11 and HDMI 2.1,
this will send a signal to the TV suggesting it to switch to
a low latency mode ("game mode").

Source/Android/app/src/main/AndroidManifest.xml

@@ -73,7 +73,8 @@
 
         <activity
             android:name=".activities.EmulationActivity"
-            android:theme="@style/DolphinEmulationBase"/>
+            android:theme="@style/DolphinEmulationBase"
+            android:preferMinimalPostProcessing="true"/>
 
         <activity
             android:name=".activities.CustomFilePickerActivity"