Returns if the given NPC class name is a friend. Returns true if the entity name is one of the following:

• monster_scientist
• monster_barney
• npc_alyx
• npc_barney
• npc_citizen
• npc_dog
• npc_eli
• npc_fisherman
• npc_gman
• npc_kleiner
• npc_magnusson
• npc_monk
• npc_mossman
• npc_odessa
• npc_vortigaunt