nwo: fabric-x notification service configuration

[mbrandenburger]

The current notification service config is hardcoded in the NWO extension for Fabric-x.

We should get the configuration details from the actual committer instance that is launched within NWO instead of using hardcoded values.

[SaidAltury-ibm]

work in integration/nwo/fabricx/extensions/scv2/notificationservice.go and change the NS extension signature to use the extension struct and retrieve the parameters from the sidecar (NS uses the same ports)