Fix issues with outdated package-lock.json file. (#1170)

Our `package-lock.json` file is outdated and our dependencies are a bit jumbled up.

I didn't notice any issue when using `nodejs14` but when using `nodejs16` reveals several issues that I've tried to address in the PR:

1. Update `typedoc` dependency to avoid impossible dep resolution (first reported #1169)

2. Regenerate `package-lock.json`. Looks like it's "behind" package.json. I took this opportunity to use `lockfileVersion: 2` which is the default if you use `nodejs16`

3. Using `firebase-admin` v10.3.0 broke some unit test we had. Fixed in 2ee9549.

Author: taeold