add network when updating server (#23839)

* add network when updating server

* fix linter

Author: xiaoxuqi-ms

specification/mysql/resource-manager/Microsoft.DBforMySQL/FlexibleServers/preview/2022-09-30-preview/FlexibleServers.json

@@ -1095,6 +1095,10 @@
         "dataEncryption": {
           "$ref": "#/definitions/DataEncryption",
           "description": "The Data Encryption for CMK."
+        },
+        "network": {
+          "$ref": "#/definitions/Network",
+          "description": "Network related properties of a server"
         }
       },
       "description": "The properties that can be updated for a server."