Revert has_parent? optimization

What does this MR do?

This reverts optimization made in !17749 (merged)

The reason is that at the moment parent_id reference integrity is not assured and a couple of errors were reported when the referenced parent was actually missing (see related issue).

I considered fixing specifically the reported error - check in first_auto_devops_config if parent is not nil, but this wouldn't fix the underlying issue and the same problem might pop up elsewhere.

Created #212144 (closed) to re-enable this when possible.

Closes #36938 (closed)

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Does this MR meet the acceptance criteria?

Conformity

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