chore: clean `lib` when running tsc (#5982)
chore: clean `lib` when running tsc (#5982)

I've had misleading type errors due to left over builds or tests
behaving oddly. We should just strip the entire folder out before
building again so there's no left over artefacts that could cause
issues.

The `|| true` in the command is so if `rm` errors because the folder
doesn't exist, it doesn't exit with an error code.
puppeteer/puppeteer,GoogleChrome/puppeteer,puppeteer/puppeteer,GoogleChrome/puppeteer,GoogleChrome/puppeteer,puppeteer/puppeteer,puppeteer/puppeteer