Only update the TM UAS if we are in request context and not fake request

[vladpaiu]

Summary
Fix crashing of OpenSIPS when script writer mistakenly runs async in branch route and/or event route

Details
In case of push notifications injecting branches, and if in branch_route the script writer does async() calls, OpenSIPS will update the UAS with information from the fake request ( which might contain new branch lumps and other changes ). In case there are multiple branches, post_print_uac_request will try to free up the new request and find old SHM branches and crash in

    /* delete inserted branch lumps */
    del_flaged_lumps( &request->add_rm, LUMPFLAG_BRANCH);
    del_flaged_lumps( &request->body_lumps, LUMPFLAG_BRANCH);

Solution
Only update the UAS if we are running in request route and we are not having a fake request in hand.

Compatibility
Backwards compatible

[github-actions]

Any updates here? No progress has been made in the last 30 days, marking as stale.

[ar45]

Should this be just if ((t->uas.request) && !(msg->msg_flags & FL_TM_FAKE_REQ)) ?