Tombstoning a V12 room to any room version < 12 can lead to loss of powerlevel

### Description

If the creator of a V12 room tombstones the room to any other room version below 12, the upgrade api sets the PL of the creator to 0 after creating the room

### Steps to reproduce

- make a V12 room
- `/upgraderoom 11` in element
- open new room
- have no power anymore

### Homeserver

matrix.org

### Synapse Version

Synapse 1.136.0 (b=matrix-org-hotfixes-priv,a4db588e87)

### Installation Method

Docker (matrixdotorg/synapse)

### Database

Postgresql

### Workers

Multiple workers

### Platform

you know better than me :)

### Configuration

_No response_

### Relevant log output

```shell
^
```

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

_No response_