Bug: Toggleable brushes don't update realtime dynamic lights

[HugoBDesigner]

When a shadow-casting func_brush is disabled while it is casting shadow from a Fully Dynamic light, the shadow persists until the light is updated or another shadow-casting object intersects it. This issues does NOT apply to enabling the brush (it'll start casting shadows as expected). A temporary fix is to manually update the light source whenever a brush is disabled, but ideally it should happen automatically.

_{Pictured: a red light was casting shadows on the toggleable brush within the frame. The brush was disabled, but the shadow persisted. A different light source (green) shows that there is no shadow-casting brush there anymore.}