stake-pool-js: export the StakePoolLayout (#7324)

* export the StakePoolLayout

* export other layouts

Author: tomjohn1028

stake-pool/js/src/index.ts

@@ -46,6 +46,7 @@ import BN from 'bn.js';
 export type { StakePool, AccountType, ValidatorList, ValidatorStakeInfo } from './layouts';
 export { STAKE_POOL_PROGRAM_ID } from './constants';
 export * from './instructions';
+export { StakePoolLayout, ValidatorListLayout, ValidatorStakeInfoLayout } from './layouts';
 
 export interface ValidatorListAccount {
   pubkey: PublicKey;