Monsters: Remove unused properties for stats

[osrsbox]

It seems there are two properties that are not being used in the monster properties and stats:

• attack_slash
• attack_stab

Not sure how they were included... but should remove them. And check the wiki monster infobox to confirm it is being parsed correctly.

[osrsbox]

Closed in 1f912b51562a1acc4a7ea974e61a51c3a5f70a11 New monster combat stat props:

combat_bonuses = {
    "attack_level": "att",
    "strength_level": "str",
    "defence_level": "def",
    "magic_level": "mage",
    "ranged_level": "range",
    "attack_bonus": "attbns",
    "strength_bonus": "strbns",
    "attack_magic": "amagic",
    "magic_bonus": "mbns",
    "attack_ranged": "arange",
    "ranged_bonus": "rngbns",
    "defence_stab": "dstab",
    "defence_slash": "dslash",
    "defence_crush": "dcrush",
    "defence_magic": "dmagic",
    "defence_ranged": "drange",
}