Fix `ci_cd_settings`, `project_feature` Import

What does this MR do?

Currently, we are not importing ci_cd_settings correctly.

It happens because of the RelationFactory logic, and how we handle EXISTING_OBJECT_CHECK in it and also with the fact that ci_cd_settings being created with the Project's after_create callback.

During the fix, it was also discovered that project_feature is imported incorrectly (for the same reason).

This MR fixes that and adding specs to prevent regressions in the future.

Resolves: #36710 (closed)

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