Gets serialized into the bool on the profile's global level.
Isn't leg specific, but global for the whole session.
Only used to remove SST related headers and option tags
from requests and replies being sent through either
`SBCCallLeg::onSendRequest()` or `SBCCallLeg::onSendReply()`.
Transparent means - do not touch existing SST headers.
SessionTimer implementation factory isn't triggered in this case.
Change-Id: Id98a8abc957be11d140eba2394fed7ebe1302ca7