Support HEIC images

### Steps to reproduce

1. Send a HEIC image to a room. (Mimetype should be `"public.heic"`.)

Example event source (some parts redacted):

```
{
"room_id": "!redacted:beeper.com",
"type": "m.room.message",
"content": {
"body": "ima_355e641",
"info": {
"size": 1182567,
"mimetype": "public.heic",
"w": 3024,
"thumbnail_file": {
"iv": "REDACTED",
"hashes": {
"sha256": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
},
"key": {
"k": "REDACTED",
"ext": true,
"key_ops": [
"encrypt",
"decrypt"
],
"alg": "A256CTR",
"kty": "oct"
},
"url": "mxc://beeper.com/0000000000000000000000000000000000000000",
"v": "v2"
},
"h": 4032
},
"file": {
"iv": "REDACTED",
"hashes": {
"sha256": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
},
"key": {
"k": "REDACTED",
"ext": true,
"key_ops": [
"encrypt",
"decrypt"
],
"alg": "A256CTR",
"kty": "oct"
},
"url": "mxc://beeper.com/0000000000000000000000000000000000000000",
"v": "v2"
},
"msgtype": "m.image"
}
}
```

### Outcome

#### What did you expect?

I expect that when I click on the thumbnail, the full image is shown.

#### What happened instead?

When I click on the thumbnail, the full image is not shown (blank screen)


### Operating system

NixOS

### Application version

Element version: 1.9.2, Olm version: 3.2.3

### How did you install the app?

From Nixpkgs

### Homeserver

nevarro.space

### Will you send logs?

No