Typo in Segment membership Id

[jbeckert]

https://github.com/adobe/xdm/blob/035d53be03861efc152cca620237751cc5ce551c/schemas/context/profile.example.1.json#L83

The segment id should probably look like the one above. It is acknowledged that this is just an example and the value could be any URI but we should be more consistent

[Soundug]

@jbeckert I would like to take this up.