Before forwarding last activity requests to a user, check that the user's presence...

Before forwarding last activity requests to a user, check that the user's presence is visible for From

According to XEP-0012, 4. Online User Query, "if the requesting entity
is not authorized to view the user's presence information (normally via
a presence subscription as defined in XMPP IM), the user's server MUST
NOT deliver the IQ-get to an available resource but instead MUST return
a <forbidden/> error in response to the last activity request."

So check for a subscription of from of the jid and bare jid and whether
outgoing presences to From are allowed.

Fixes problem 3 of EJAB-1158.