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
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).