I left all the spaces I am in and I cannot reach my DMs

### Steps to reproduce

1. Left all rooms in all spaces (from desktop nightly client)
2. It will stuck on the last space you were rendering
3. No ways to list rooms that are not in any spaces

### Outcome

#### What did you expect?
- Fallback to render "all chats"
- "All chats" is enabled if I create a dummy space with an empty room

#### What happened instead?
- Locked in last rendered spaces
- Only available option is to create new space


### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

_No response_

### Homeserver

_No response_

### Will you send logs?

Yes

### Are you willing to provide a PR?

No

Reproduce the problem by leaving all rooms in all spaces and observing the last rendered space, then compare it with the expected fallback to "all chats." Trace the spaces and room-list navigation entry points involved; done means users can still reach rooms outside spaces without creating a dummy space.

Written by the indexing model from the issue text.