sleeper component schedules wake/sleep test tasks even when entities are offscreen

This happens on component creation and/or when assigning a custom sleep/wake test.

Despite these implying this shouldn't be the case, very likely for performance reasons, given how many offscreen entities in the world can be scheduling these tasks:

function Sleeper:OnEntitySleep()
    self:StopTesting()
end

function Sleeper:OnEntityWake()
    self:StartTesting()
end

This can simply be addressed by adding a check like this, maybe with an extra one if you do want offscreen sleeping to be a thing for some entities.

function Sleeper:StartTesting(time)
    if self.inst:IsAsleep() then
        return
    end

    if self.isasleep then
        self:SetTest(ShouldWakeUp, time)
    else
        self:SetTest(ShouldSleep)
    end
end