chore: clean up unnecessary webdriverio/spectron references

[dbjorge]

Details

This PR removes some unnecessary code and an unnecessary dependency on webdriverio that became obsolete when we switched the unified e2e tests from spectron to playwright. Per the comment in dependabot.yml, we were only using webdriverio for typings shared between it and spectron; it isn't required anymore.

I also removed a few other lingering bits of dead code related to Spectron while I was here (eg, a bunch of timeout constants that we stopped using with the move to playwright).

Motivation

Originally, this was part of a PR to resolve a CG alert against the async package. The non-dev dependencies on async were resolved by other PRs and the specific CG alert in question isn't applicable to dev dependencies, so it's no longer necessary to do any further resolutions for async; however, I kept this bit of the PR since removing the unnecessary code still seemed nice.

Context

n/a

Pull request checklist

• [n/a] Addresses an existing issue: #0000
• Ran yarn fastpass
• [n/a] Added/updated relevant unit test(s) (and ran yarn test)
• [n/a] Verified code coverage for the changes made. Check coverage report at: <rootDir>/test-results/unit/coverage
• PR title AND final merge commit title both start with a semantic tag (fix:, chore:, feat(feature-name):, refactor:). See CONTRIBUTING.md.
• [n/a] (UI changes only) Added screenshots/GIFs to description above
• [n/a] (UI changes only) Verified usability with NVDA/JAWS