az backup protection backup-now: Add support for two-phase snapshot full backup for SAP HANA

### Preconditions

- [x] No need to upgrade Python SDK or the Python SDK is ready.

### Related command

az backup protection backup-now

### Resource Provider

Microsoft.RecoveryServices (for the Backup Vault) and Microsoft.Compute (for the VM snapshots)

### Description of Feature or Work Requested

Title: az backup protection backup-now: Add support for two-phase snapshot full backup for SAP HANA

Issue Summary:
Currently, the Azure CLI command az backup protection backup-now for SAP HANA instances uses the legacy streaming (Backint) method, which proceeds directly to the "Transfer data to vault" phase.

Discrepancy:
In the Azure portal, the "Backup now" operation for the same SAP HANA instance uses the newer, more efficient snapshot method, which creates a two-phase job:

Take Snapshot: Combines an Azure managed disk snapshot with HANA snapshot commands.

Transfer data to vault: Transfers the snapshot data to the Recovery Services vault.

Why this is needed:
The snapshot method provides instant backups and restores, which is critical for production SAP HANA environments. The current CLI limitation creates an automation gap, forcing a choice between the more advanced manual portal process and less efficient automated scripts.

Requested Feature:
Add a parameter (e.g., --SnapshotFull) or a new command to the az backup protection backup-now workflow that allows triggering the two-phase snapshot full backup for SAP HANA database instances via the Azure CLI.

### Minimum API Version Required

N/A

### Swagger PR link / SDK link

not sure

### Request Example

_No response_

### Target Date

2026-04-15

### PM Contact

Srinath Vasireddy

### Engineer Contact

Anurag Mehrotra

### Additional context

_No response_