chore(actions): Disable to run "Issue/PR response" workflow on forks

[ViacheslavKudinov]

Resolves #2857

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Before the change?

• "Issue/PR response" workflow always runs on forks if not to disable it on Actions tab

After the change?

• ✅ Adds condition to run "Issue/PR response" workflow only on integrations/terraform-provider-github repository, but to skip run on forks

Pull request checklist

• Schema migrations have been created if needed (example)
• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes
• No

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