refactor(client): Add overloads for application command create and edit methods.

[elenakrittik]

Summary

Adds overloads to Client.[create|edit]_[guild|global]_command() methods to make typing for them more precise.

Checklist

• If code changes were made, then they have been tested
  • I have updated the documentation to reflect the changes
  • I have formatted the code properly by running pdm lint
  • I have type-checked the code by running pdm pyright
• 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, ...)

[shiftinv]

thanks!