Admin can't demote me in a room

This issue has been migrated from [#16519](https://github.com/matrix-org/synapse/issues/16519).

---

### Description

There is a public room where I am moderator and do not have permissions to change power levels. And this does not work.

I have therefore asked an admin to demote me and they are getting this error

```
Failed to change power level M_FORBIDDEN: MatrixError: [403] You don't have permission to post that to the room. user_level (0) < send_level (100) (https://matrix-client.matrix.org/_matrix/client/v3/rooms/!YTvKGNlinIzlkMTVRl%3Amatrix.org/state/m.room.power_levels/)
```

### Steps to reproduce

- Demote user

### Homeserver

matrix.org

### Synapse Version

latst

### Installation Method

Docker (matrixdotorg/synapse)

### Database

?

### Workers

I don't know

### Platform

?

### Configuration

_No response_

### Relevant log output

```shell
I don't have access to the logs
```

### Anything else that would be useful to know?

Room ID: `!YTvKGNlinIzlkMTVRl:matrix.org`