Add Example LB3 Tests to lb3-application

[nabdelgadir]

Follow-up for #5251.

To demonstrate migration of LB3 tests when it is mounted on an LB4 application, add example LB3-style tests to lb3-application.

Acceptance criteria

• Add example acceptance tests
• Add example integration tests (blocked by Bind Mounted LB3 Models to LB4 Context #5299)
• Add example authentication tests

[jannyHou]

Closing after #5403 merged.