We sometimes forget to remove focused or disabled annotations after debugging tests. This of course isn't ideal and as brought up in #8485 we should add checks against this. Therefore, this PR:

• Adds the eslint-plugin-jest package which contains a bunch of jest-syntax-specific rules
• Enables the no-focused-tests rule to throw a lint error if a test is focused with it.only, fit or similar functions.
• Enables the no-disabled-tests rule to throw a lint error if a test (suite) from a suite is disabled/skipped with it.skip, xit or similar functions. While we sometimes skip tests on purpose, I'd argue that we generally want to avoid this, as it can also happen accidentally. For the few exceptions of this rule, we can always ignore it.

If reviewers want to avoid adding another dependency to the project, we can also extract the rules and vendor them. However, I'd argue that adding eslint-plugin-jest is probably the simplest way to enable this rules and we might want to enable other rules in the future (e.g. no-conditional-expects).

This rule also works with vitest syntax which we use in the SvelteKit package.

Limitation: Our Playwright browser integration tests use a custom test function (sentryTest instead of test) which these rules cannot detect. I tried setting the global aliases setting but it didn't work because sentryTest is imported and hence not considered a global. We can revisit adding a custom rule for this later.