fix: include gas fees in user operations when using a paymaster (#4032)

## Explanation

### Description:
When a paymaster is used, the user operation still requires the
inclusion of gas fee values (`maxFeePerGas` and `maxPriorityFeePerGas`)
to enable the bundler and entrypoint to charge the paymaster
appropriately. This PR addresses an issue where the gas fees are
currently lost and submitted as empty to the bundler when using a
paymaster.

### Changes:
Detect when [getTransactionMetadata has set the gas fees to zero because
the userOperation has a
paymaster](https://github.com/MetaMask/core/blob/af668da3c09b62a43ae1f6c91bfd1a0f4241a610/packages/user-operation-controller/src/utils/transaction.ts#L86-L90)
and do not update the user operation gas fees.

## References

<!--
Are there any issues that this pull request is tied to? Are there other
links that reviewers should consult to understand these changes better?

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* Fixes #12345
* Related to #67890
-->
* Fixes MetaMask/MetaMask-planning#2180

## Changelog

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### `@metamask/user-operation-controller`

- **FIXED**: include gas fees in user operations when using a paymaster

## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've highlighted breaking changes using the "BREAKING" category
above as appropriate

packages/user-operation-controller/src/UserOperationController.test.ts

@@ -871,6 +871,46 @@ describe('UserOperationController', () => {
         );
       });
 
+      it('does not update gas fees nor regenerate if paymaster is set but updated gas fees are zero', async () => {
+        const controller = new UserOperationController(optionsMock);
+
+        approvalControllerAddRequestMock.mockResolvedValue({
+          value: {
+            txMeta: {
+              txParams: {
+                ...ADD_USER_OPERATION_REQUEST_MOCK,
+                maxFeePerGas: '0x0',
+                maxPriorityFeePerGas: '0x0',
+              },
+            },
+          },
+        });
+
+        const { hash, id } = await addUserOperation(
+          controller,
+          ADD_USER_OPERATION_REQUEST_MOCK,
+          {
+            ...ADD_USER_OPERATION_OPTIONS_MOCK,
+            smartContractAccount,
+          },
+        );
+
+        await hash();
+
+        expect(controller.state.userOperations[id].userOperation).toStrictEqual(
+          expect.objectContaining({
+            maxFeePerGas: '0x4',
+            maxPriorityFeePerGas: '0x5',
+          }),
+        );
+        expect(smartContractAccount.prepareUserOperation).toHaveBeenCalledTimes(
+          1,
+        );
+        expect(smartContractAccount.updateUserOperation).toHaveBeenCalledTimes(
+          1,
+        );
+      });
+
       it('regenerates if gas fees updated and paymaster data set', async () => {
         const controller = new UserOperationController(optionsMock);
 

packages/user-operation-controller/src/UserOperationController.ts

@@ -770,10 +770,21 @@ export class UserOperationController extends BaseController<
     const previousMaxFeePerGas = userOperation.maxFeePerGas;
     const previousMaxPriorityFeePerGas = userOperation.maxPriorityFeePerGas;
 
-    if (
+    const gasFeesUpdated =
       previousMaxFeePerGas !== updatedMaxFeePerGas ||
-      previousMaxPriorityFeePerGas !== updatedMaxPriorityFeePerGas
-    ) {
+      previousMaxPriorityFeePerGas !== updatedMaxPriorityFeePerGas;
+
+    /**
+     * true when we detect {@link getTransactionMetadata} has set the gas fees to zero
+     * because the userOperation has a paymaster. This should not be mistaken for gas
+     * fees being updated during the approval process.
+     */
+    const areGasFeesZeroBecauseOfPaymaster =
+      usingPaymaster &&
+      updatedMaxFeePerGas === VALUE_ZERO &&
+      updatedMaxPriorityFeePerGas === VALUE_ZERO;
+
+    if (gasFeesUpdated && !areGasFeesZeroBecauseOfPaymaster) {
       log('Gas fees updated during approval', {
         previousMaxFeePerGas,
         previousMaxPriorityFeePerGas,