Better test helpers for pathManagedByEno

[jveski]

Overrides that use pathManagedByEno on arrays are difficult to get right, since different types of arrays in the k8s api scheme generate managedFields entries that use different keys. For example: map arrays will use the key field (typically name) instead of a numeric index. In these cases pathManagedByEno only works as expected if the correct index is used.

We should add unit test helpers that use real openapi documents to verify override path and condition expressions.