[MXKRoomDataSource] Warning: The user does not know the room XXX

[d232b57]

Describe the bug
By following the MatrixSDK use case 4, I can post a text message to a room.
But by following the MatrixKit use case 1, an error occurred "[MXKRoomDataSource] Warning: The user does not know the room XXX".

To Reproduce

MXKRoomDataSourceManager *roomDataSourceManager = [MXKRoomDataSourceManager sharedManagerForMatrixSession:SESSION];
MXKRoomViewController *roomViewController = [[MXKRoomViewController alloc] init];

[roomDataSourceManager roomDataSourceForRoom:ROOM_ID create:YES onComplete:^(MXKRoomDataSource *roomDataSource) {
    [roomViewController displayRoom:roomDataSource];
    [UIApp.keyWindow.rootViewController presentViewController:roomViewController animated:YES completion:nil];
}];

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: iPad mini 4
• OS: iOS14.0
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[d232b57]

Encrypted rooms not supported! #783