[mgmt sql] Deprecate SqlSyncGroup / SqlSyncMember in azure-resourcemanager-sql (SQL Data Sync retirement)

[XiaofeiCao]

Summary

Deprecate the SQL Data Sync related fluent APIs in azure-resourcemanager-sql, including (but not limited to):

• com.azure.resourcemanager.sql.models.SqlSyncGroup (and its SqlSyncGroupOperations, SqlSyncGroupActionsDefinition)
• com.azure.resourcemanager.sql.models.SqlSyncMember (and its SqlSyncMemberOperations, SqlSyncMemberActionsDefinition)
• Related entry points on SqlDatabase (getSyncGroups(), syncGroups()).

Background

Azure SQL Data Sync is scheduled for retirement. In addition, SQL Data Sync only supports SQL authentication (static username/password) for connections to the hub and member databases — it does not support Microsoft Entra (Azure AD) authentication or managed identities. This conflicts with modern security guidance (MFA, Conditional Access, managed identities, password rotation policies).

Context: this was raised during PR review #49163 (comment), where tests for SqlSyncGroup / SqlSyncMember still require SQL authentication and could not be migrated to Entra-only authentication.

Proposed action

1. Mark the SQL Data Sync related classes/methods listed above as @Deprecated in azure-resourcemanager-sql, with Javadoc explaining:
   • SQL Data Sync is scheduled for retirement by Azure.
   • These APIs require SQL authentication and do not support Microsoft Entra ID / managed identity.
   • Users should migrate to an alternative that aligns with their organization's security standards.
2. Recommend alternatives in the Javadoc / changelog, such as:
   • Azure SQL Managed Instance link feature or failover groups / geo-replication for HA/DR scenarios.
   • Azure Data Factory / Synapse pipelines for data movement / replication scenarios.
   • Change Data Capture (CDC) / Change Tracking combined with the above for incremental sync.
   • Transactional replication for on-prem ⇄ Azure SQL DB scenarios.
3. Update CHANGELOG.md of azure-resourcemanager-sql to call out the deprecation and recommended alternatives.
4. Add a comment to the existing tests (SqlServerOperationsTests#canCRUDSqlSyncMember, etc.) noting that SQL Data Sync requires SQL authentication, which is why those tests cannot use Entra-only auth.

References

• SQL Data Sync docs (retirement notice + auth limitation): https://learn.microsoft.com/azure/azure-sql/database/sql-data-sync-data-sql-server-sql-database?view=azuresql
• PR review comment: mgmt, sql , fix live test failures #49163 (comment)

/cc @weidongxu-microsoft