Remove warning logs from frontend tests

[daquinons]

This fixes the way that the handler was throwing the error, which somehow was generating all the unrelated warning logs in the tests.

It also redirects to the dashboard if the changeRequest ID can't be found instead of displaying errors.

Checklist

Remove any items which are not applicable.

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works AND the tests pass

[daquinons]

Fix warnings in frontend tests