Fix: stash account reaped when ledger.active == ED (#8170)

* do not reap account when active == ed

* add tests + refactor

substrate/frame/staking/src/lib.rs

@@ -1638,7 +1638,7 @@ decl_module! {
 				ledger = ledger.consolidate_unlocked(current_era)
 			}
 
-			let post_info_weight = if ledger.unlocking.is_empty() && ledger.active <= T::Currency::minimum_balance() {
+			let post_info_weight = if ledger.unlocking.is_empty() && ledger.active < T::Currency::minimum_balance() {
 				// This account must have called `unbond()` with some value that caused the active
 				// portion to fall below existential deposit + will have no more unlocking chunks
 				// left. We can now safely remove all staking-related information.
@@ -3080,7 +3080,7 @@ impl<T: Config> Module<T> {
 	/// Assumes storage is upgraded before calling.
 	///
 	/// This is called:
-	/// - after a `withdraw_unbond()` call that frees all of a stash's bonded balance.
+	/// - after a `withdraw_unbonded()` call that frees all of a stash's bonded balance.
 	/// - through `reap_stash()` if the balance has fallen to zero (through slashing).
 	fn kill_stash(stash: &T::AccountId, num_slashing_spans: u32) -> DispatchResult {
 		let controller = <Bonded<T>>::get(stash).ok_or(Error::<T>::NotStash)?;