Add safety check for unknown inventory items
Add safety check for unknown inventory items

When adding/removing features, without migration, there are sometimes
items (in the database) with IDs that are not valid anymore.

This fix makes it so that unknown items are simply ignored.

A3Armory/A3A_A3Wasteland_Sock.Altis,A3Armory/A3A_A3Wasteland_Sock.Chernarus,A3Armory/A3A_A3Wasteland_Sock.Altis,A3Armory/A3A_A3Wasteland_Sock.Altis,micovery/ArmA3_Wasteland.Altis,A3Armory/A3A_A3Wasteland_Sock.Chernarus,micovery/ArmA3_Wasteland.Altis,A3Armory/A3A_A3Wasteland_Sock.Chernarus