[Microsoft.DeviceUpdate][Internal Only] Fixed RPaaS linter error - provisioningState (Azure#18328)

* Fixed RPaaS linter error - provisioningState

* Linter fixes

* Added description

Author: darkoa-msft

specification/deviceupdate/resource-manager/Microsoft.DeviceUpdate/preview/2020-03-01-preview/deviceupdate.json

@@ -1597,7 +1597,20 @@
         {
           "$ref": "#/definitions/PrivateEndpointConnectionProxyProperties"
         }
-      ]
+      ],
+      "properties": {
+        "properties": {
+          "description": "Private endpoint connection proxy object property bag.",
+          "type": "object",
+          "x-ms-client-flatten": true,
+          "properties": {
+            "provisioningState": {
+              "$ref": "#/definitions/PrivateEndpointConnectionProxyProvisioningState",
+              "description": "The provisioning state of the private endpoint connection proxy resource."
+            }
+          }
+        }
+      }
     },
     "PrivateEndpointConnectionProxyProperties": {
       "description": "Private endpoint connection proxy object properties.",
@@ -1613,10 +1626,6 @@
           "description": "Remote private endpoint details.",
           "$ref": "#/definitions/RemotePrivateEndpoint"
         },
-        "provisioningState": {
-          "$ref": "#/definitions/PrivateEndpointConnectionProxyProvisioningState",
-          "description": "The provisioning state of the private endpoint connection proxy resource."
-        },
         "status": {
           "description": "Operation status.",
           "type": "string"