Bump undici and discord.js

Bumps [undici](https://github.com/nodejs/undici) to 6.13.0 and updates ancestor dependency [discord.js](https://github.com/discordjs/discord.js/tree/HEAD/packages/discord.js). These dependencies need to be updated together.


Updates `undici` from 5.27.2 to 6.13.0
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.27.2...v6.13.0)

Updates `discord.js` from 14.14.1 to 14.15.2
- [Release notes](https://github.com/discordjs/discord.js/releases)
- [Changelog](https://github.com/discordjs/discord.js/blob/main/packages/discord.js/CHANGELOG.md)
- [Commits](https://github.com/discordjs/discord.js/commits/14.15.2/packages/discord.js)

---
updated-dependencies:
- dependency-name: undici
  dependency-type: indirect
- dependency-name: discord.js
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>