docs(universal): fix issues with inconsistent documentation

[yharaskrik]

Checklist

• Issue number for this PR: #nnn (required)
• Docs included?: (yes/no; required for all API/functional changes) yes
• Test units included?: (yes/no; required) no
• In a clean directory, yarn install, yarn test run successfully? (yes/no; required) yes

Description

Docs for the Universal/Cloud Functions integration were out of date, this PR updates them so that a full working reproduction can work from start to finish with additional information for Firebase

Code sample