MNT Set title_format for unit test

[emteknetnz]

Issue https://github.com/silverstripeltd/product-issues/issues/897

Fixes https://github.com/silverstripe/recipe-kitchen-sink/actions/runs/14297765069/job/40067128555#step:12:329

I'm kind of surprised this passed when it was originally merged

[GuySartorelli]

LGTM.

For context, CWP is changing this config in https://github.com/silverstripe/cwp/blob/3/_config/config.yml which is causing this test to fail in SINK but not in framework or other recipe test suites.

This change just puts the configuration in a predictable state, which is what you want for a test.