fluffychat struggles with SVG files

[anarcat]

Bug Description

I can't seem to select an SVG icon for a room in Fluffychat. I can pick a PNG, but the file picker (at least in Linux desktop), doesn't consider "image files" to include SVG.

Steps to Reproduce

1. go to a room
2. in the three dots menu, pick "room details"
3. click on the camera
4. "open gallery"
5. see only PNG images, no SVG

also:

1. click on the "+" sign next to the chat line
2. choose "send file"
3. pick a SVG file
4. click send ("send original" doesn't matter)
5. see the following backtrace:

Null check operator used on a null value
#0      MatrixImageFile.resizeImplementation (package:matrix/src/utils/matrix_file.dart:258)
#1      NativeImplementationsDummy.shrinkImage (package:matrix/src/utils/native_implementations.dart:117)
#2      compute.<anonymous closure> (package:flutter/src/foundation/_isolates_io.dart:19)
#3      _RemoteRunner._run (dart:isolate:1090)
#4      _RemoteRunner._remoteExecute (dart:isolate:1084)
#5      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:300)
#6      _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184)

and finally:

1. upload a SVG from Element into a room
2. go into Fluffychat
3. look at room, SVG looks like this:

Note that fluffychat doesn't seem to render SVG icons in rooms avatars either, but i'm less sure of that.

Expected Behavior

I should be able to upload SVG files to rooms. Failing this, I shouldn't get a backtrace, and I should be able to just upload the file without fluffychat trying (and failing) to do a conversion).

For what it's worth, Element is fine uploading, viewing, and setting as avatar, SVG files.

App Version

1.22.1

Additional Platform Information

Debian bookworm, installed through flatpak

Additional Context

This is similar to #299 which was closed for inactivity, but is still relevant.