[BUG] Storage Account doesn't clear sasPolicy via PUT

[magodo]

API Spec link

https://github.com/Azure/azure-rest-api-specs/blob/main/specification/storage/resource-manager/Microsoft.Storage/stable/2023-01-01/storage.json

API Spec version

2023-01-01

Describe the bug

I have a storage account created with sasPolicy defined:

    "sasPolicy": {
      "expirationAction": "Log",
      "sasExpirationPeriod": "1.15:5:05"
    },

Then I want to use PUT to update the storage account by leaving sasPolicy absent:

{
  "identity": {
    "type": "None",
    "userAssignedIdentities": null
  },
  "kind": "StorageV2",
  "location": "westus2",
  "properties": {
    "accessTier": "Hot",
    "allowBlobPublicAccess": true,
    "allowCrossTenantReplication": false,
    "allowSharedKeyAccess": true,
    "defaultToOAuthAuthentication": false,
    "dnsEndpointType": "Standard",
    "encryption": {
      "keySource": "Microsoft.Storage",
      "services": {
        "blob": {
          "enabled": true,
          "keyType": "Account",
          "lastEnabledTime": "2024-12-23T01:03:34.7455723Z"
        },
        "file": {
          "enabled": true,
          "keyType": "Account",
          "lastEnabledTime": "2024-12-23T01:03:34.7455723Z"
        }
      }
    },
    "isHnsEnabled": false,
    "isLocalUserEnabled": true,
    "isNfsV3Enabled": false,
    "isSftpEnabled": false,
    "minimumTlsVersion": "TLS1_2",
    "networkAcls": {
      "bypass": "AzureServices",
      "defaultAction": "Allow",
      "ipRules": [],
      "resourceAccessRules": [],
      "virtualNetworkRules": []
    },
    "publicNetworkAccess": "Enabled",
    "supportsHttpsTrafficOnly": true
  },
  "sku": {
    "name": "Standard_LRS",
    "tier": "Standard"
  },
  "tags": {}
}

(correlation request id: bf194019-4316-4982-a915-0b668273c8e3)

Whilst the response of the above request still returns the sasPolicy un-changed.

Expected behavior

The PUT with no sasPolicy shall remove the sasPolicy from the model per the definition of PUT.

Actual behavior

sasPolicy is stil there.

Reproduction Steps

As is mentioned above.

Environment

No response