Unable to load thumbnail image with enable_authenticated_media=True

### Description

Unable to load thumbnail image with enable_authenticated_media=True, crashes with NotFoundError in class ThumbnailProvider method respond_local_thumbnail

### Steps to reproduce

- l in homeserver.py enable_authenticated_media=True
- upload image via UploadServlet on_POST
- download thumbnail ThumbnailResource on_GET

### Homeserver

localhost

### Synapse Version

1.134.0

### Installation Method

pip (from PyPI)

### Database

PostgreSQL

### Workers

Single process

### Platform

docker

### Configuration

_No response_

### Relevant log output

```shell
response {
"errcode": "M_NOT_FOUND",
"error": "Not found"
}
```

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

_No response_