Update cloud ClickHouse CI environment variables to production instance

[Copilot]

Summary

Migrates cloud test workflow to use production ClickHouse instance secrets by updating environment variable names with _PROD suffix.

Created .github/workflows/run-tests-cloud.yml with:

• Secret names: INTEGRATIONS_TEAM_TESTS_CLOUD_HOST_SMT_PROD, INTEGRATIONS_TEAM_TESTS_CLOUD_PASSWORD_SMT_PROD, INTEGRATIONS_TEAM_TESTS_CLOUD_JWT_DESERT_VM_43_PROD
• Matrix testing: Go oldstable and stable versions
• SSL-enabled cloud connection (no Docker)
• Explicit contents: read permissions for GITHUB_TOKEN security

Checklist

Delete items not relevant to your PR:

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG
• For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

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