fix(ApplicationCommandManager): limit permission methods to guilds

[vaporoxx]

Please describe the changes this PR makes and why it should be merged:

These endpoints are not available for global commands.

Status and versioning classification:

• I know how to update typings and have done so
• This PR includes breaking changes (methods removed or renamed, parameters moved or removed)

[SpaceEEC]

Maybe also add a <warn>ing in the ApplicationCommand methods docstrings?

[advaith1]

This method cannot be used on global application commands.

This is incorrect: global commands can have permissions, but the permissions must be set per-server

[vaporoxx]

Yes, but that needs to be done through the manager, so saying "This method cannot be used" on the command class method is still correct

[vladfrangu]

CC @iCrawl @kyranet

stale