MT#60476 Session lvl `sdp_attr_print` in `sdp_out_add_other`
Move printing of other session level attributes (so taken
from the coming SDP and to be carried out to the outgoing one)
to a dedicated function `sdp_out_add_other()`.
No functional change.
Change-Id: I94713545e7610d74d36a6a5f3027c64407c6750c