message: chore(sdk-core): add keepAlive option to PrebuildTransactionOptions
  We want to allow users to determine whether or not to use the
  keepAlive flag with Polkadot's transferAll functionality.
  Add this as a generalized Prebuild flag to allow for future
  use as well as use in Polkadot tx building.
  TICKET:
diff: @@ -107,6 +107,7 @@ export interface PrebuildTransactionOptions {
  isTss?: boolean;
  custodianTransactionId?: string;
  apiVersion?: ApiVersion;
  + keepAlive?: boolean;
  }
  export interface PrebuildAndSignTransactionOptions extends PrebuildTransactionOptions, WalletSignTransactionOptions {
  