Single frame GIFs turned into video

[GlitchyPSIX]

Steps to Reproduce

1. Create a GIF file that consists of only 1 frame.
2. Use the post composer to upload the GIF.
3. Post.

Attachments

Result from GIFs with 1 frame

https://bsky.app/profile/eramdam.me/post/3lbxmffhkuc26

What platform(s) does this occur on?

Web (Desktop), potentially affects all other platforms too

Device Info

Windows 10 22H2 + Vivaldi 7.0.3495.18 (Stable channel) (64 bits)

What version of the app are you using?

Bluesky 1.95

Additional Information

This was introduced as a result of #6433 .
Uploading a GIF with no data that results in animation will produce a different error relating to the video length.

Attached is one such GIF as well, although it might be out of scope.

[SpriterGors]

Reminder that this implicates in higher bandwidth usage because an image file is usually smaller than a video file, which is, of course, not good for Bluesky servers.