Sticker uploading doesn't work in v14

[advaith1]

Which package is this bug report for?

discord.js

Issue description

Sticker creation works in v13 but in v14, you get DiscordAPIError[50046]: Invalid Asset. I think it's an issue in djs/rest, but I'm not 100% sure.

This can be seen by simply running the first example in https://discord.js.org/#/docs/discord.js/main/class/GuildStickerManager?scrollTo=create.

When running identical code with Routes.guildStickers and Routes.channelMessages, the latter works but the former returns the error.

I've been debugging this for an hour but can't figure it out.

Code sample

No response

Package version

14.0.0-dev.1657757514-fe34f48

Node.js version

v16.15.1

Operating system

Windows 11 22H2 25151.1010

Priority this issue should have

Medium (should be fixed soon)

Which partials do you have configured?

Not applicable (subpackage bug)

Which gateway intents are you subscribing to?

Not applicable (subpackage bug)

I have tested this issue on a development release

No response