Videos fail to send

[lorenzo132]

Describe the bug
Videos are unable to send in either dm and in a thread.

Bot Info
Bot version (check with @modmail about): 3.7.13 / 3.8.0dev7
Host method (Heroku, self-host, etc): vps

To Reproduce
Steps to reproduce the behavior:

1. Who can reproduce (ex. anyone, owners)? Anyone
2. Where can it be reproduced (ex. in thread channels, recipient DM's)? in dms and in the thread channel
3. Done what to cause the error? Send a video
4. Any recently made changes to your bot? No recent changes
5. Errored

Error Logs
If your Modmail bot is online, type @modmail debug hastebin and include the link here. https://hastebin.cc/ruvewaqasa
If your Modmail bot is not online or the previous command did not generate a link, do the following:

1. Select your bot application at https://dashboard.heroku.com
2. Restart your bot
3. Reproduce the error to populate the error logs
4. Copy and paste the logs

Screenshots
in dm: https://cdn.discordapp.com/attachments/770408630788816917/795364717542637568/b40476b15eba9944.png

In thread channel: https://cdn.discordapp.com/attachments/770408630788816917/795364938583375912/unknown.png

Additional context
Add any other context about the problem here.

[fourjr]

This issue applies to all non-image files as well and is fixed in v3.8