Fix RTL icon mirroring in DevReportActivity

For some reason, the toolbar icon has a wrong layout direction,
so the autoMirrored attribute doesn't take any effect.

briar-android/src/main/res/drawable-ldrtl/social_send_now_white.xml

+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportHeight="24.0"
+        android:viewportWidth="24.0">
+	<!-- Workaround for toolbar icons failing to apply proper layout direction -->
+	<group
+		android:pivotX="12"
+		android:pivotY="12"
+		android:rotation="180">
+		<path
+			android:fillColor="#FFFFFFFF"
+			android:pathData="M2.01,21L23,12 2.01,3 2,10l15,2 -15,2z"/>
+	</group>
+</vector>

briar-android/src/main/res/drawable/social_send_now_white.xml

 <vector xmlns:android="http://schemas.android.com/apk/res/android"
         android:width="24dp"
         android:height="24dp"
-        android:autoMirrored="true"
         android:viewportHeight="24.0"
         android:viewportWidth="24.0">
 	<path