restor extension pop up fragment

packages/flutter_mozilla_components/android/src/main/res/layout/activity_add_on_settings.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?><!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:fitsSystemWindows="true">
+
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/addonSettingsContainer"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

packages/flutter_mozilla_components/android/src/main/res/layout/fragment_add_on_settings.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<androidx.coordinatorlayout.widget.CoordinatorLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_height="match_parent">
+
+    <mozilla.components.concept.engine.EngineView
+        tools:ignore="Instantiatable"
+        android:id="@+id/addonSettingsEngineView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>