Update dialog UI and search view hint font

1. Dialog title should place center and use custom font.
2. Search view hint font should same as search bar font.
3. Sort list text should use custom font.
4. Update BottomSheetDialog parent to theme overlay style, so we can
   remove redundant style on values-night.
5. Update DocumentsDefaultTheme parent to DayNight theme, this theme
   is control normal and night res in lib, so we can remove redundant
   style on values-night.

Fix: 132038131
Fix: 132038826
Test: visual
Test: atest DocumentsUIGoogleTests
Change-Id: I01e1e097b9f9df29f5ec432409befbcec8a128db