Set last_service_data in the right place

[basnijholt]

I noticed this changed after #598

@protyposis, was this intentional?

[protyposis]

What exactly do you mean re #598? I can't see any last_service_data-related changes in there.

To be honest, I never completely understood its purpose, and so I tried to keep this as untouched as I could. But the change you made in here seems reasonable :)

[th3w1zard1]

iirc the last time we touched last_service_data was during the migration from the old detect_non_ha_changes code. This PR's change would affect #512 but it doesn't seem like we're planning on using that PR anyway.

[basnijholt]

I believe the only thing that changed is that currently the code can set self.manager.last_service_data[light] = service_data and in some next step it can terminate early before light.turn_on has been called.

Upon further inspection I think this shouldn't matter and I don't think it breaks anything.

I have been reading all changes in detail since there have been some unexplainable errors that people have reported 😅

I also realized that it's always been incorrect for the separate_turn_on_commands because there the last_service_data is set to the pre-split version of it. This PR is the correct fix I believe.