Bring back the on_finalize weight of staking. (#8463)

* Bring back the on_finalize weighg of stakin.

* Better logs

* Also make a few things pub

* Fix build

* Add assertions

* Add test.

* remove dbg

* Update frame/election-provider-multi-phase/src/unsigned.rs

* Update frame/staking/src/tests.rs

* Fix

* Fix

* Update frame/election-provider-multi-phase/src/unsigned.rs

substrate/frame/staking/src/tests.rs

@@ -3827,6 +3827,14 @@ fn do_not_die_when_active_is_ed() {
 		})
 }
 
+#[test]
+fn on_finalize_weight_is_nonzero() {
+	ExtBuilder::default().build_and_execute(|| {
+		let on_finalize_weight = <Test as frame_system::Config>::DbWeight::get().reads(1);
+		assert!(Staking::on_initialize(1) >= on_finalize_weight);
+	})
+}
+
 mod election_data_provider {
 	use super::*;
 	use frame_election_provider_support::ElectionDataProvider;