refactor: simplify ExtraInvitationMaker (#10044)

refs: #10023

## Description
@0xpatrickdev points out it doesn't need to return a vow

### Security Considerations
n/a
### Scaling Considerations
n/a

### Documentation Considerations
n/a

### Testing Considerations
Should not affect tests

### Upgrade Considerations
undeployed

packages/orchestration/src/examples/staking-combinations.contract.js

@@ -6,7 +6,6 @@
  * actions with an ICA account.
  */
 import { AmountShape } from '@agoric/ertp';
-import { VowShape } from '@agoric/vow';
 import { M } from '@endo/patterns';
 import { prepareCombineInvitationMakers } from '../exos/combine-invitation-makers.js';
 import { CosmosOrchestrationInvitationMakersInterface } from '../exos/cosmos-orchestration-account.js';
@@ -50,15 +49,10 @@ const emptyOfferShape = harden({
  * @param {Zone} zone
  * @param {OrchestrationTools} tools
  */
-const contract = async (
- zcf,
- privateArgs,
- zone,
- { orchestrateAll, vowTools },
-) => {
+const contract = async (zcf, privateArgs, zone, { orchestrateAll }) => {
  const ExtraInvitationMakerInterface = M.interface('', {
- DepositAndDelegate: M.call(M.array()).returns(VowShape),
- UndelegateAndTransfer: M.call(M.array()).returns(VowShape),
+ DepositAndDelegate: M.call(M.array()).returns(M.promise()),
+ UndelegateAndTransfer: M.call(M.array()).returns(M.promise()),
  });
  /** @type {any} XXX async membrane */
  const makeExtraInvitationMaker = zone.exoClass(
@@ -72,7 +66,7 @@ const contract = async (
  DepositAndDelegate() {
  const { account } = this.state;
 
- const invP = zcf.makeInvitation(
+ return zcf.makeInvitation(
  (seat, validatorAddr, amountArg) =>
  // eslint-disable-next-line no-use-before-define -- defined by orchestrateAll, necessarily after this
  orchFns.depositAndDelegate(account, seat, validatorAddr, amountArg),
@@ -84,24 +78,20 @@ const contract = async (
  },
  },
  );
-
- return vowTools.watch(invP);
  },
  /**
  * @param {Omit<Delegation, 'delegatorAddress'>[]} delegations
  */
  UndelegateAndTransfer(delegations) {
  const { account } = this.state;
 
- const invP = zcf.makeInvitation(
+ return zcf.makeInvitation(
  // eslint-disable-next-line no-use-before-define -- defined by orchestrateAll, necessarily after this
  () => orchFns.undelegateAndTransfer(account, delegations),
  'Undelegate and transfer',
  undefined,
  emptyOfferShape,
  );
-
- return vowTools.watch(invP);
  },
  },
  );