Bump sha.js and web-ext

Removes [sha.js](https://github.com/crypto-browserify/sha.js). It's no longer used after updating ancestor dependency [web-ext](https://github.com/mozilla/web-ext). These dependencies need to be updated together.


Removes `sha.js`

Updates `web-ext` from 7.12.0 to 8.9.0
- [Release notes](https://github.com/mozilla/web-ext/releases)
- [Commits](mozilla/web-ext@7.12.0...8.9.0)

---
updated-dependencies:
- dependency-name: sha.js
  dependency-version: 
  dependency-type: indirect
- dependency-name: web-ext
  dependency-version: 8.9.0
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]