Rangecard - fix CTD on weapons with invalid configs

[PabstMirror]

"ace" callExtension ["ballistics:zero_advanced",[200,0,6.69248,15,1013.25,0,0.5,1,"ICAO"]]
will crash game, key number probably is 2nd (muzzle velocity of 0)

can reproduce with western sahri AA12

todo:

• handle in extension as well

panicked at extension\src\ballistics\drag.rs:167:45:
attempt to subtract with overflow

• look into AA12 configs and why calculateBarrelLengthVelocityShift is returning 0

[PabstMirror]

some bad weapons in our modset DSA_XTS, ptv_bm4, CUP_sgun_SPAS12, CUP_sgun_AA12, CUP_sgun_slamfire, cwr3_sgun_kozlice
mostly shotguns

they have a barrelLen set for the gun but nothing for the ammo configs so ace_advanced_ballistics_fnc_calculateBarrelLengthVelocityShift returns 0
and calling the ext with 0 mv caused the crash

both issues should now be fixed