Crash after calling DendriteMonolith.stop()

*This issue was originally created by [**@Juha-Park-TII**](https://github.com/Juha-Park-TII) at .*

### Background information

- **Dendrite version or git SHA**: 0.8.7
- **Monolith or Polylith?**: Monolith
- **SQLite3 or Postgres?**: No Idea
- **Running in Docker?**: No
- **`go version`**: go1.17.7 darwin/amd64
- **Client used (if applicable)**:

### Description

- **What** is the problem: When Dendrite monolith in android stop, it crashes
- **Who** is affected: Dendrite in Android
- **How** is this bug manifesting: E/GoLog: time="2022-06-07T08:59:02.988851880Z" level=fatal msg="accept tcp 127.0.0.1:65432: use of closed network connection"
- **When** did this first appear: it happens all the time regardless of dendrite version when dendrite server is stopped

### Steps to reproduce

- list the steps
1. monolith = DendriteMonolith()
2. monolith ?.storageDirectory = applicationContext.filesDir.toString()
3. monolith ?.cacheDirectory = applicationContext.cacheDir.toString()
4. monolith ?.start()
5. monolith?.stop()
- that reproduce the bug
- using hyphens as bullet points

Start at DendriteMonolith.stop() and follow the listener shutdown path that produces the reported fatal "use of closed network connection" message. Reproduce the Android monolith start/stop sequence with the listed storage and cache directories, then verify that stopping the server completes without a crash or fatal log.

Written by the indexing model from the issue text.