fix(http): escape / in url parameters

[shiftinv]

Summary

See https://docs.python.org/3.12/library/urllib.parse.html#urllib.parse.quote.

This doesn't pose an immediate risk, but is still something that should not be happening.
See also discordjs/discord-api-types@1ba3472 and h1 #2765008.

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, ...)