Convert interaction.data["guild_id"] to int in the KeyError fallback within process_application_commands

[NeloBlivion]

Fixes the KeyError fallback in process_application_commands to actually function.

Summary

If an application command can't be found by its interaction ID, there's a fallback that attempts to find it by checking the command name and its guild_ids if they are set. However, the guild_id in interaction.data is a string while SlashCommand.guild_ids is a list of integers and so this would always fail, further resulting in commands being unregistered.

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, typehinting, examples, ...)

[NeloBlivion]

Test: Got ctx.interaction.data from a slash-based eval and used its data to emulate the check used in bot.py