Fix various problems with notification layouts

- Fix end padding for inbox notification.
- Fix that actions in BigText were clipped off.
- Fix that second line was never shown.
- Fix top padding in combination with badges.
- Fix that actions in InboxStyle were clipped off.
- Make badge style consistent with small icon.
- Fix that third line on Inbox/BigText is always 12sp (before it was
  sometimes 14sp)

Bug: 17315502
Bug: 17285898
Bug: 17311783
Bug: 17200814
Change-Id: Ic7e5e4fa07b6302a76631d0238b88239871acf49