V5 update tests documentation

[helendduncan]

✅ Checklist

• I have searched open and closed issues for duplicates
• This is a request for a change to documentation
• This isn't a feature request or bug report
• This isn't an open-ended question (open a discussion if it is).

📒 Where is the problem?

The most recent reference to smoke tests is in the V4.2.2 docs

📝 Required documentation changes

Update path to tests
Tests need to be run as root (sudo -i)

[JimMadge]

I think also the tests need to be run from the directory they are in /usr/local/bin/smoke_tests.

Not certain if they must be run as root but we can test that. Hard to tell when #2336 means the smoke tests will fail.