fix: remove validator set position from storage when slashing

Author: brentstone

proof_of_stake/src/lib.rs

@@ -3249,6 +3249,9 @@ where
                     .at(&epoch)
                     .at(&token::Amount::from_change(amount_pre))
                     .remove(storage, &val_position)?;
+                validator_set_positions_handle()
+                    .at(&epoch)
+                    .remove(storage, validator)?;
 
                 // For the pipeline epoch only:
                 // promote the next max inactive validator to the active
@@ -3305,6 +3308,9 @@ where
                     .at(&epoch)
                     .at(&token::Amount::from_change(amount_pre).into())
                     .remove(storage, &val_position)?;
+                validator_set_positions_handle()
+                    .at(&epoch)
+                    .remove(storage, validator)?;
             }
             ValidatorState::BelowThreshold => {
                 println!("Below-threshold");