[3006.x] Allow runas to accept compound commands

[twangboy]

What does this PR do?

Allows runas to run compound commands (commands joined by &&)

I tried writing some tests, but I don't know how to do it as another user. It requires the username and password for that user.

What issues does this PR fix or reference?

Fixes: #44736

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• [ ] Docs
• [ ] Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• [ ] Tests written/updated

Commits signed with GPG?

Yes