feat(zero_trust_organization): add migration test

[ssicard]

• I understand that this repository is auto-generated and my pull request may not be merged

Changes being requested

Tests zero_trust_organization during v4 to v5 migration. This is an import only resource, and so the test pattern does not test resource creation like most other migration test. It does basic structure validation and tests import functionality.

Acceptance test run results

• I have added or updated acceptance tests for my changes
• I have run acceptance tests for my changes and included the results below

Steps to run acceptance tests

TF_ACC=1 TF_MIGRATE_BINARY_PATH=/Users/ssicard/workspace/terraform-devstack/tf-migrate/tf-migrate go test -v -run "TestMigrate" ./internal/services/zero_trust_organization

Test output

=== RUN   TestMigrateZeroTrustOrganization_Import
--- PASS: TestMigrateZeroTrustOrganization_Import (1.16s)
=== RUN   TestMigrateZeroTrustOrganization_ImportStructureValidation
    migrations_test.go:227: ✓ Import structure validation passed
--- PASS: TestMigrateZeroTrustOrganization_ImportStructureValidation (0.71s)
PASS
ok  	github.com/cloudflare/terraform-provider-cloudflare/internal/services/zero_trust_organization	3.192s

Additional context & links