Adjust nextElected to use erasStakersOverview (#6011)

Author: TarikGul

packages/api-derive/src/staking/validators.ts

@@ -12,11 +12,11 @@ import { memo } from '../util/index.js';
 export function nextElected (instanceId: string, api: DeriveApi): () => Observable<AccountId[]> {
   return memo(instanceId, (): Observable<AccountId[]> =>
     // Compatibility for future generation changes in staking.
-    api.query.staking.erasStakersPaged
+    api.query.staking.erasStakersOverview
       ? api.derive.session.indexes().pipe(
         // only populate for next era in the last session, so track both here - entries are not
         // subscriptions, so we need a trigger - currentIndex acts as that trigger to refresh
-        switchMap(({ currentEra }) => api.query.staking.erasStakersPaged.keys(currentEra)),
+        switchMap(({ currentEra }) => api.query.staking.erasStakersOverview.keys(currentEra)),
         // Dedupe any duplicates
         map((keys) => [...new Set(keys.map(({ args: [, accountId] }) => accountId.toString()))].map((a) => api.registry.createType('AccountId', a)))
       )