Newly created backstage identity user entities from signing in with auth providers are not ingested into catalog

[Zaperex]

Describe the bug

Currently the backend creates a new backstage identity for the user if no matching user entity is found in the catalog.

However this identity isn't populated into the catalog so no such user entity would actual exist for the signed-in user.

Expected Behavior

Either disallow authenticating without a valid user entity in the catalog, or ingest the user entity once user has authenticated with one of the supported providers.

What are the steps to reproduce this bug?

1. Authenticate with any provider (in the screenshots above I am using the azure (microsoft) auth provider)
2. Sign-in and view the Backstage Identity in the settings
3. Click on the User Entity
4. Observe that user entity does not exist in catalog

Versions of software used and environment

[PatAKnight]

I was thinking about this earlier this morning: I believe we should not allow users to be authenticated if they are not present within the software catalog. However, I am curious about others' thoughts on the subject.