fix(tests): add default packet serializers

feat(tests): add tests for command processor, walk command handler, stateful injector

fix(packets): make UpgradeRareSubPacket converter work with "0"

feat(tests): add player test with 0 UpgradeRareSubPacket

chore: update tests

fix(packets): make bs packet effect id nullable

fix: correct usings

fix(game): make rest of effects vnum short instead of long

chore: update versions

feat(packets): make skill vnum in su packet nullable

feat(combat): support self targeted and area skills

feat(game): handle null skill vnum in su packet responder

fix(game): create character on at packet received

fix(game): make effects vnum short instead of long

fix(combat): do not return successfully when walk position is equal to target position

fix(packets): add header for st sub packet

chore: bump versions to support new PacketSerializer

chore: update Game

chore: fix workflow to work with .net 7

chore: update PacketSerializer version