GFI-564: support gw rules internal dns settings

[sebassimoes]

adding support to configure internal dns settings on gateway resolver rules.

[github-actions]

changelog detected ✅

[jacobbednarz]

acceptance tests all passing

TF_ACC=1 go test ./internal/sdkv2provider -v -run "^TestAccCloudflareTeamsRule_" -count 1 -timeout 120m -parallel 1
=== RUN   TestAccCloudflareTeamsRule_Basic
--- PASS: TestAccCloudflareTeamsRule_Basic (4.21s)
=== RUN   TestAccCloudflareTeamsRule_NoSettings
--- PASS: TestAccCloudflareTeamsRule_NoSettings (3.42s)
=== RUN   TestAccCloudflareTeamsRule_CustomResolver
--- PASS: TestAccCloudflareTeamsRule_CustomResolver (2.64s)
=== RUN   TestAccCloudflareTeamsRule_WithClipboardRedirection
--- PASS: TestAccCloudflareTeamsRule_WithClipboardRedirection (2.51s)
PASS
ok      github.com/cloudflare/terraform-provider-cloudflare/internal/sdkv2provider      13.367s

[github-actions]

This functionality has been released in v4.51.0 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!