tooling: fix "cannot find module eslint" error when running "build-misskey-js-with-types"

What does this MR do?

Fixes an error where pnpm run build-misskey-js-with-types throws an error because of missing eslint.

Contribution Guidelines

By submitting this merge request, you agree to follow our Contribution Guidelines

• I agree to follow this project's Contribution Guidelines
• I have made sure to test this merge request

added tooling label

requested review from @julia, @Marie, and @dakkar

how does it work without that dependency declaration?

approved this merge request

resolved all threads

approved this merge request

mentioned in commit ecd7e803

merged