Implement getWorkAdult

[darthnithin]

Solves a todo. getWorkAdult implemented by checking if the work is rated NR, M, or E.
Had to modify a test because the test case was wrong.

[darthnithin]

genuinly i don't know why all those commits come with the PR

[essential-randomness]

since this is a constant, we should define it outside this function like this:

const ADULT_CATEGORIES: WorkRatings[] = [WorkRatings.EXPLICIT, WorkRatings.MATURE, WorkRatings.NOT_RATED];
export const getWorkAdult = ($workPage: WorkPage): boolean => {
// rest of the code

see https://google.github.io/styleguide/tsguide.html#identifiers-constants (but it's a common convention)

[essential-randomness]

Also, I just found out about this: https://mkosir.github.io/typescript-style-guide/#type-safe-constants-with-satisfies

Apparently the best way of declaring this constant would be:

const ADULT_CATEGORIES = [
  WorkRatings.EXPLICIT, 
  WorkRatings.MATURE, 
  WorkRatings.NOT_RATED
] as const satisfies ReadonlyArray<WorkRatings>;

this would give the most correct typing (feel free to ask if you want to understand more).

I'd be ok with keeping it const ADULT_CATEGORIES: WorkRatings[], but since you're changing it let's try the new one?