Sole user in 1:1 room is no longer allowed to post messages

### Steps to reproduce

I have been using two (encrypted) rooms only for myself, with a single Matrix account, no other Matrix account was ever invited.

A search for "Waiting for users to join" yielded https://github.com/vector-im/element-web/issues/24865 which also appears in a "Room (with only myself)"; but that issue looks different from what I've been experiencing.

### Outcome

A recent version of Element-FDroid no longer permits me to post in those rooms; no text input field is shown. Other sessions of the same Matrix account (using Element-Desktop or an old version of Element-FDroid) can still post in those rooms.

One of the two rooms contains only a few posts and shows the message "Waiting for users to join" at the top. In the other room I can't scroll back far enough to be able to see the top; I can only guess that it shows the same message.

By coincidence, I found that changing a room from being a 1:1 chat to being a group chat (`/converttoroom`) resolved the issue; though I'd much prefer the two rooms to not be listed among other group chats.

I'd say that making that change in behaviour was not a good idea. At least the explanation ("Element does not let you post anything until someone else has joined this 1:1 room.") should be moved to the place where the user expects the input field. Assuming the new restriction does serve some purpose for newly created 1:1 rooms, maybe it could be dropped if the room already contains posts.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

Element-FDroid 1.5.32

### Homeserver

hosted by EMS

### Will you send logs?

No

### Are you willing to provide a PR?

No