Getting custom keys onTimeline updated Snapshot[SDK]

### Description

I am adding a some custom keys to my message content while sending event, now when I get the message in my `onTimeLineUpdated Listener` there the custom keys are getting removed if the message is a reply to another message.

For eg :-
I am replying to a message with custom key as `attachment` which is list of custom data type.
Here's my json which I send :-
```
"{m.relates_to={m.in_reply_to={event_id=eventId}}, attachments=[{info={mtype=m.image, name=Happy Birthday GIF by Rodney Dangerfield.image/gif, size=0, type=image/gif}, url={content_uri=attachmentUrlHere}}], body=, msgtype=m.text, formatted_body=}"
```

Now, when I get this in `onTimelinUpdate` it removes `attachments` key from the object but when I try to get the TimeLineEvent with :- `roomService?.getRoom(roomId)?.getTimelineEvent(id)` it gives me all the things in my response.

Also in my message if I change `m.relates_to` to any other key like `m.attachment_relates_to` then it works and give all the things as expected.

It only happens in Android Sdk, other then that iOS, Web and others work fine.