tooling: Update eslint to v9; update dependencies

[marcustyphoon]

This updates eslint to v9, which requires a new configuration file format, as well as updating our other dependencies; notably, web-ext 9.2.0 also uses eslint 9 internally.

I did not bother installing eslint-plugin-jsdoc, which is one of the migrations for eslint 9 (as its built-in jsdoc rules have been removed).

This also updates transitive dependencies, resolving 3 security warnings.

[nightpool]

what was the blocker for the jsdoc dependencies? I feel like they were one of the most useful parts of eslint

[marcustyphoon]

No blocker, per se! I just considered this MVP. eslint-plugin-jsdoc's defaults consider most of our jsdoc invalid, so it just needs a bunch of rule-fiddling.