Accidentally broke CI in #58891

Since
https://github.com/zed-industries/zed/blob/c68bc98bacb80c34df0e1b6ef4de186d763b3820/crates/feature_flags/src/store.rs#L180
defaults to true in debug mode (effectively sets staff to `true`) the
tests would fail.

We can work around this by manually disabling the feature flag for tests
in settings.

Also, since we are planning to ship to preview tomorrow these tests will
be removed soon.


Release Notes:

- N/A