Fix bug causing status to be cleared after adding Finalizer

[gravufo]

Description of your changes

This PR will fix the issue where the status sub-object would be cleared when adding the Finalizer. This would cause Observe-only resources to wait until the next SyncPeriod/PollPeriod to become Ready=true even though it should have been set at the first loop.

Fixes #791

Note: I am really unsure if these are the right places to do those changes, so please don't hesitate to leave comments pointing to the right locations.

I have:

• [x] Read and followed Crossplane's [contribution process].
• [x] Run earthly +reviewable to ensure this PR is ready for review.
• [x] Added or updated unit tests.
• [ ] Linked a PR or a [docs tracking issue] to [document this change].
• [ ] Added backport release-x.y labels to auto-backport this PR.