feat(rulesets): add state migration to clean up removed fields

[jacobbednarz]

Follows on from #4697 to cleanup the state automatically.

[github-actions]

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[github-actions]

This functionality has been released in v4.48.0 of the Terraform Cloudflare Provider.

Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!