How to turn off a light sensor LED light?
The white &quot;screws&quot;, are knockout plugs. A knockout is simply a hole where conduit, cable, wire, or a device can attach/enter the box. A knockout plug, is used to fill unused knockouts.
Here is a similar box cover with the knockouts unplugged.

This allows you to attach devices, like lamp holders and motion sensors.

Any extra holes would be filled with a plug.


Professional Help
You should be able to hire an Electrician to install a switch as you mention, but it would depend on if you have the legal right to (own vs. rent, etc.)