Features
- Added stringSet for date format and applied them
Key Value DATE_FORMAT__MESSAGE_CREATED_AT 'p'DATE_FORMAT__UNREAD_SINCE 'p MMM dd'DATE_FORMAT__LAST_MESSAGE_CREATED_AT__TODAY 'p'DATE_FORMAT__LAST_MESSAGE_CREATED_AT__THIS_YEAR 'MMM d'DATE_FORMAT__LAST_MESSAGE_CREATED_AT__PREVIOUS_YEAR 'yyyy/M/d'