Create Thread deleted state UI for when root message removed

[daniellekirkwood]

Your use case

When the root message is deleted, still allow access to the thread

• Design

Requirements

• Making sure that a thread can still be viewed even if the root message has been deleted

[daniellekirkwood]

Removing Jano's assignment as Designs have been added to the issue

[daniellekirkwood]

This was identified as a "fail" in the testing on January 20, 2022 as there was no "message deleted" placeholder in the room timeline or thread timeline.

[janogarcia]

@daniellekirkwood Actually I logged those issues for iOS, not Android, on January 22 session:

• The root message in the thread wont show the "Message deleted" status until the app is reopened.
• The deleted root message and its thread summary completely disappear from the main timeline on reopening the app.

[daniellekirkwood]

Drats. Ok, I will move this to the iOS repo