Make stickers effective on players

[Mooncat]

Request: make the "sticker" entities to be effective on the "player" entities.

In the current version, "sticker" cannot be added on "player". When you throw a slowdown capsule to any enemy player on a PVP map, the capsule will not do anything to that player. Ideally, it can apply effects on "player" entities, just like how it does on "unit" entities.