Re: [sr-dev] [kamailio/kamailio] [RFE]: Allow NULL for acc db_extra and multi_leg_info (#2531)

I have more testing to do, apparently -- there are times where `multi_leg_info` variables are all set to `NULL` in the DB (without error), although they are defined and printed properly in the syslog. I've tried moving the modparam `multi_leg_info` above and below modparam `acc_extra_nullable`, but the results seem random. I'll see what else I can find and report back, but so far this only seems to affect the `multi_leg_info` variables -- the `db_extra` ones are always inserted properly.