Fix for issue #1477

[daniel-pro]

fix for "oci_certificates_management_certificate fails with config_type="IMPORTED" #1477" issue.

all credits to @bscarbrough

This is a new PR, the previous one (PR #2240) was accidentally closed by mistake when I removed my forked repo.

[tf-oci-pub]

Thank you for your valuable contribution. We greatly appreciate your efforts in submitting this pull request. However, I regret to inform you that we are unable to merge it directly on GitHub at this time.

Our internal policy requires that all pull requests undergo thorough local testing and review before they can be merged into the main codebase. This process ensures the quality and stability of Terraform-Provider-OCI.

We understand that this may cause some inconvenience, but please rest assured that your contribution is highly valued. Our team will carefully review and test your changes locally to ensure they meet our standards.

We appreciate your understanding and patience in this matter. If you have any questions or need further assistance, please don't hesitate to reach out. Thank you once again for your contribution.