Proof-of-concept for broken feature flag detection

In project2/crates/crate1/lib.rs there is a struct HasFieldsWithFeatureFlags which has a field only_feat_1 that is only available if the feature feat1 is turned on, but RustRover doesn't understand that the feature isn't turned on in project1/src/lib.rs and says

Missing field in `HasFieldsWithFeatureFlags` initializer: `only_feat_1`

Which it shouldn't do because the feature isn't turned on.