build improvement: enable no-explicit-any ESLint rule as an error

[43081j]

This should already be throwing warnings unless we disabled it explicitly.

We should:

• Change the level to error
• Remove all possible eslint-ignore lines which currently disable this rule
• Remove all usages of any

We have quite a few, so i expect this'll be a sizeable change.

There will inevitably be some we have to keep around, too, because of dependencies typing them poorly (e.g. overriding a dependency's method which has any in its signature).

[wooorm]

👍

Maybe useful: https://github.com/plantain-00/type-coverage