{AzureDataProtection} fixes #21183 (#21551)

fixes #21183

The enum values for the storage settings are listed in the latest API as `ArchiveStore, SnapshotStore, VaultStore.`
However while providing `SnapshotStore` value it fail with `BMSUserErrorInvalidInput` error. Also while trying the same from PS cmdlet using

> New-AzDataProtectionBackupVaultStorageSettingObject -DataStoreType SnapshotStore -Type LocallyRedundant

**Error:**
```
Error: "Unable to match the identifier name 
SnapshotStore to a valid enumerator name. Specify one of the following enumerator names and try again:
ArchiveStore, OperationalStore, VaultStore"
```

This PR fixes the enum value of storage setting

specification/dataprotection/resource-manager/Microsoft.DataProtection/stable/2022-05-01/dataprotection.json

@@ -6113,7 +6113,7 @@
           "description": "Gets or sets the type of the datastore.",
           "enum": [
             "ArchiveStore",
-            "SnapshotStore",
+            "OperationalStore",
             "VaultStore"
           ],
           "type": "string",