Disabled Accelerated Networking for VMSS in migration flow (#247)

Migration flow uses assessment based VMSS sku and not all of them support Accelerated Networking. By default, Accelerated Networking will be disabled in migration flow and enabled as per need.

migration/azuredeploy-migration.json

@@ -244,6 +244,7 @@
                     "vNetAddressSpace":             { "value": "[parameters('vNetAddressSpace')]"},
                     "ubuntuVersion":                { "value": "[parameters('ubuntuVersion')]"},
                     "location":                     { "value": "[variables('location')]" },
+                    "enableAccelNwForOtherVmsSwitch":   { "value" : false },
                     "isMigration":                  { "value": true }
                 },
                 "templateLink": {