dendrite-demo-yggdrasil. Invalid memory address or nil pointer dereference

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

### Background information
* Commit: 11fd2f019bb6325155c2fa825b82c1fbef07b300
* Database: PostgreSQL 14
* Manual build
* Go v1.20.3
* OS: Linux Mint 21.2 (based on Ubuntu 22.04)

### Description
Running:
```
cd /opt/dendrite
./bin/dendrite-demo-yggdrasil -config dendrite.yaml
```
Output:
```
INFO[2023-08-30T14:17:14.529017168Z] Dendrite version 0.13.2+11fd2f0
INFO[2023-08-30T14:17:14.531194306Z] TCP listener started on [::]:44685
INFO[2023-08-30T14:17:14.531606986Z] Public key: ae9046f7e60313d90e7b5d65c5addd4f0f887f40dc1b426c620f94249f2235dc
INFO[2023-08-30T14:17:14.533415082Z] TLS listener started on [fe80::5abb:e497:e8f6:e502%enp3s0]:43135
DEBU[2023-08-30T14:17:14.536699872Z] Setting DB connection limits conn_max_lifetime=-1s data_source_name="postgresql://127.0.0.1:5432/dendrite-yggdrasil?sslmode=disable" max_idle_conns=5 max_open_conns=90
INFO[2023-08-30T14:17:14.537723780Z] Connected inbound TLS: 224:f743:b01d:7e01:ceaa:8ff7:8291:accc@[fe80::5abb:e497:e8f6:e502%enp3s0]:49381, source [fe80::5abb:e497:e8f6:e502%enp3s0]:43135
INFO[2023-08-30T14:17:14.590434044Z] Starting nats-server component=jetstream
INFO[2023-08-30T14:17:14.590482411Z] Version: 2.9.19 component=jetstream
INFO[2023-08-30T14:17:14.590526983Z] Git: [not set] component=jetstream
INFO[2023-08-30T14:17:14.590564854Z] Name: monolith component=jetstream
INFO[2023-08-30T14:17:14.590601662Z] Node: 2VDOOQDB component=jetstream
INFO[2023-08-30T14:17:14.590645182Z] ID: NAQVNJ7U6MJE44ANIV3BRG2FOTG53YA23OESP5CK57AWIZZIWYYGDNA7 component=jetstream
WARN[2023-08-30T14:17:14.590696912Z] Maximum payloads over 8.00 MB are generally discouraged and could lead to poor performance component=jetstream
INFO[2023-08-30T14:17:14.590812319Z] Starting JetStream component=jetstream
INFO[2023-08-30T14:17:14.591387993Z] _ ___ _____ ___ _____ ___ ___ _ __ __ component=jetstream
INFO[2023-08-30T14:17:14.591428535Z] _ | | __|_ _/ __|_ _| _ \ __| /_\ | \/ | component=jetstream
INFO[2023-08-30T14:17:14.591461428Z] | || | _| | | \__ \ | | | / _| / _ \| |\/| | component=jetstream
INFO[2023-08-30T14:17:14.591507591Z] \__/|___| |_| |___/ |_| |_|_\___/_/ \_\_| |_| component=jetstream
INFO[2023-08-30T14:17:14.591645318Z] component=jetstream
INFO[2023-08-30T14:17:14.591682846Z] https://docs.nats.io/jetstream component=jetstream
INFO[2023-08-30T14:17:14.591744095Z] component=jetstream
INFO[2023-08-30T14:17:14.591812954Z] ---------------- JETSTREAM ---------------- component=jetstream
INFO[2023-08-30T14:17:14.591949492Z] Max Memory: 11.63 GB component=jetstream
INFO[2023-08-30T14:17:14.592140819Z] Max Storage: 33.01 GB component=jetstream
INFO[2023-08-30T14:17:14.592408239Z] Store Directory: "jetstream" component=jetstream
INFO[2023-08-30T14:17:14.592447028Z] ------------------------------------------- component=jetstream
INFO[2023-08-30T14:17:14.593007534Z] Starting restore for stream '$G > DendriteInputDeviceListUpdate' component=jetstream
INFO[2023-08-30T14:17:14.593584815Z] Restored 0 messages for stream '$G > DendriteInputDeviceListUpdate' component=jetstream
INFO[2023-08-30T14:17:14.594098125Z] Starting restore for stream '$G > DendriteInputRoomEvent' component=jetstream
INFO[2023-08-30T14:17:14.594742457Z] Restored 0 messages for stream '$G > DendriteInputRoomEvent' component=jetstream
INFO[2023-08-30T14:17:14.594902885Z] Starting restore for stream '$G > DendriteInputSigningKeyUpdate' component=jetstream
INFO[2023-08-30T14:17:14.595379842Z] Restored 0 messages for stream '$G > DendriteInputSigningKeyUpdate' component=jetstream
INFO[2023-08-30T14:17:14.595529140Z] Starting restore for stream '$G > DendriteOutputClientData' component=jetstream
INFO[2023-08-30T14:17:14.595986004Z] Restored 0 messages for stream '$G > DendriteOutputClientData' component=jetstream
INFO[2023-08-30T14:17:14.596146336Z] Starting restore for stream '$G > DendriteOutputKeyChangeEvent' component=jetstream
INFO[2023-08-30T14:17:14.596637297Z] Restored 0 messages for stream '$G > DendriteOutputKeyChangeEvent' component=jetstream
INFO[2023-08-30T14:17:14.596804604Z] Starting restore for stream '$G > DendriteOutputNotificationData' component=jetstream
INFO[2023-08-30T14:17:14.597279415Z] Restored 0 messages for stream '$G > DendriteOutputNotificationData' component=jetstream
INFO[2023-08-30T14:17:14.597441105Z] Starting restore for stream '$G > DendriteOutputReceiptEvent' component=jetstream
INFO[2023-08-30T14:17:14.597968539Z] Restored 0 messages for stream '$G > DendriteOutputReceiptEvent' component=jetstream
INFO[2023-08-30T14:17:14.598119644Z] Starting restore for stream '$G > DendriteOutputRoomEvent' component=jetstream
INFO[2023-08-30T14:17:14.598608793Z] Restored 0 messages for stream '$G > DendriteOutputRoomEvent' component=jetstream
INFO[2023-08-30T14:17:14.598765122Z] Starting restore for stream '$G > DendriteOutputSendToDeviceEvent' component=jetstream
INFO[2023-08-30T14:17:14.599212855Z] Restored 0 messages for stream '$G > DendriteOutputSendToDeviceEvent' component=jetstream
INFO[2023-08-30T14:17:14.599469762Z] Server is ready component=jetstream
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xfa19bc]

goroutine 1 [running]:
github.com/matrix-org/dendrite/roomserver/internal/query.(*Queryer).QueryLeftUsers(...)
/opt/dendrite/roomserver/internal/query/query.go:900
github.com/matrix-org/dendrite/userapi/internal.(*DeviceListUpdater).CleanUp(0xc00366ae60)
/opt/dendrite/userapi/internal/device_list_update.go:205 +0x163
github.com/matrix-org/dendrite/userapi.NewInternalAPI(0xc000514230, 0xc000289800, 0xc000508001?, 0x40?, {0x7f6b85e16620?, 0xc00369c000}, {0x7f6b85e16680?, 0xc000142b40})
/opt/dendrite/userapi/userapi.go:105 +0xd05
main.main()
/opt/dendrite/cmd/dendrite-demo-yggdrasil/main.go:216 +0x1529
```

### Steps to reproduce
- install and configuring Yggdrasil
- install Go 1.20 and change alternatives for /usr/bin/go
- clone Dendrite repo
- build binary files
- copy dendrite-sample.yaml as dendrite.yaml
- change a database connection string in dendrite.yaml
- running

Start by reproducing the crash with cmd/dendrite-demo-yggdrasil/main.go and the supplied PostgreSQL setup. Read roomserver/internal/query/query.go:900 and userapi/internal/device_list_update.go:205, following the call from userapi/userapi.go:105. Done means startup completes without the nil pointer dereference and the affected cleanup path is covered by an appropriate regression test.

Written by the indexing model from the issue text.