res_pjsip: On partial transport reload also move factories.

For connection oriented transports PJSIP uses factories to
produce transports. When doing a partial transport reload
we need to also move the factory of the transport over so
that anything referencing the transport (such as an endpoint)
has the factory available.

ASTERISK-29441

Change-Id: Ieae0fb98eab2d9257cad996a1136e5a62d307161