The `before_type_cast` method sometimes returns a string for
`message_type`, creating inconsistencies in different payloads. This
pull request will remove all `before_type_cast` usage and replace it
with `to_i` methods.
- Strip search term before searching
- order messages by created_at desc
- order contacts by last_activity_at desc
- order conversations by created_at desc
- Search only resolved contacts
- Optimize resolved contacts query
ref: #6583
