compute: add SNP_SVSM_CAPABLE and SEV_LIVE_MIGRATABLE_V2 to guest_os_features enum

Add `SNP_SVSM_CAPABLE` to the `guest_os_features` enum for
`google_compute_image` and `google_compute_region_disk`.

The GCP Compute API already returns `SNP_SVSM_CAPABLE` on newer images
(e.g. Ubuntu 24.04 based), but the provider's ValidateEnum rejects it,
causing plan failures on import and force-replacement of existing images.

Also adds `SEV_LIVE_MIGRATABLE_V2` to RegionDisk.yaml which was already
present in Image.yaml but missing from RegionDisk.

Fixes validation errors like:
  expected guest_os_features.0.type to be one of [...], got SNP_SVSM_CAPABLE

Author: Edgar Garcia

mmv1/products/compute/Image.yaml

@@ -143,6 +143,7 @@ properties:
             - 'SUSPEND_RESUME_COMPATIBLE'
             - 'TDX_CAPABLE'
             - 'SEV_LIVE_MIGRATABLE_V2'
+            - 'SNP_SVSM_CAPABLE'
   - name: 'imageEncryptionKey'
     type: NestedObject
     description: |

mmv1/products/compute/RegionDisk.yaml

@@ -368,6 +368,8 @@ properties:
             - 'SEV_SNP_CAPABLE'
             - 'SUSPEND_RESUME_COMPATIBLE'
             - 'TDX_CAPABLE'
+            - 'SEV_LIVE_MIGRATABLE_V2'
+            - 'SNP_SVSM_CAPABLE'
   - name: 'licenses'
     type: Array
     description: Any applicable license URI.