Simplify phone auth layout (#860)

Author: SUPERCILEX

auth/src/main/res/layout/fui_activity_register_phone.xml

@@ -1,13 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout
+<FrameLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/fragment_verify_phone"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:orientation="vertical">
-
-    <FrameLayout
-        android:id="@+id/fragment_verify_phone"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content" />
-
-</LinearLayout>
+    tools:ignore="MergeRootFrame" />