Fix DarkMode for DatePickerDialogFragment

Summary:
Fix DarkMode for DatePickerDialogFragment

changelog: [Android][Fixed] Fix DarkMode on Calendar DateTimePicker

Reviewed By: JoshuaGross

Differential Revision: D34092084

fbshipit-source-id: 4fbe3484bc7101c4b7d244671d7d46cae1c23bec

Author: mdvacca

ReactAndroid/src/main/res/shell/values/styles.xml

@@ -19,11 +19,12 @@
         <item name="android:datePickerMode">spinner</item>
     </style>
 
-    <style name="CalendarDatePickerDialog" parent="Theme.AppCompat.Light.Dialog" tools:targetApi="lollipop">
+    <style name="CalendarDatePickerDialog" parent="android:Theme.Material.Dialog.Alert" tools:targetApi="lollipop">
         <item name="android:datePickerStyle">@style/CalendarDatePickerStyle</item>
+        <item name="android:windowIsFloating">true</item>
     </style>
 
-    <style name="CalendarDatePickerStyle" parent="android:Widget.Material.Light.DatePicker" tools:targetApi="lollipop">
+    <style name="CalendarDatePickerStyle" parent="android:Widget.Material.DatePicker" tools:targetApi="lollipop">
         <item name="android:datePickerMode">calendar</item>
     </style>