[ReleasePR workloads] Adds identity type to patch monitor request. (#2408)

Create to sync Azure/azure-rest-api-specs#19206
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...azure-sdk:sdkAuto/workloads?expand=1)

Author: msftbot[bot]

schemas/2021-12-01-preview/Microsoft.Workloads.json

@@ -13,6 +13,17 @@
             "2021-12-01-preview"
           ]
         },
+        "identity": {
+          "oneOf": [
+            {
+              "$ref": "#/definitions/UserAssignedServiceIdentity"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "Managed service identity (user assigned identities)"
+        },
         "location": {
           "type": "string",
           "description": "The geo-location where the resource lives"
@@ -82,6 +93,17 @@
             "2021-12-01-preview"
           ]
         },
+        "identity": {
+          "oneOf": [
+            {
+              "$ref": "#/definitions/UserAssignedServiceIdentity"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "Managed service identity (user assigned identities)"
+        },
         "name": {
           "type": "string",
           "description": "Name of the provider instance."
@@ -1375,6 +1397,17 @@
             "2021-12-01-preview"
           ]
         },
+        "identity": {
+          "oneOf": [
+            {
+              "$ref": "#/definitions/UserAssignedServiceIdentity"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "Managed service identity (user assigned identities)"
+        },
         "name": {
           "type": "string",
           "description": "Name of the provider instance."