Replace location `h-adr` with a raw value

As noticed when trying to integrate XRay with this service, it appears that the location was missing the value field which means that it could not be parsed by a well-formed MF2 parser.

However, looking into it with aaronpk, it was noted that maybe the location information wasn't quite the best (due to street-address not always being just the address).

By reverting this back to just a string value, this is more helpful, but a bit less meaningful (in some cases).