[DatePicker] Replace fragment container with FragmentContainerView

As suggested in https://developer.android.com/reference/androidx/fragment/app/FragmentContainerView

Resolves #2490

PiperOrigin-RevId: 416323969

Author: drchen

build.gradle

@@ -32,7 +32,7 @@ ext {
     core                  : '1.5.0',
     drawerlayout          : '1.1.1',
     experimental          : '1.0.0',
-    fragment              : '1.0.0',
+    fragment              : '1.2.5',
     lifecycle             : '2.0.0',
     recyclerView          : '1.0.0',
     recyclerViewSelection : '1.0.0',

lib/java/com/google/android/material/datepicker/res/layout/mtrl_picker_dialog.xml

@@ -28,7 +28,7 @@
     android:layout_height="match_parent"
     android:orientation="vertical">
 
-    <FrameLayout
+    <androidx.fragment.app.FragmentContainerView
       android:id="@+id/mtrl_calendar_frame"
       android:layout_width="match_parent"
       android:layout_height="0dp"

lib/java/com/google/android/material/datepicker/res/layout/mtrl_picker_fullscreen.xml

@@ -24,7 +24,7 @@
 
   <include layout="@layout/mtrl_picker_header_fullscreen"/>
 
-  <FrameLayout
+  <androidx.fragment.app.FragmentContainerView
       android:id="@+id/mtrl_calendar_frame"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"