feat(STX-169): test disable transaction-controller automatic gas fee update (#6671)

## Explanation

The goal of this PR is to make sure the automatic gas fee update is
disabled when `isAutomaticGasFeeUpdateEnabled` returns false.

## References

* Related to MetaMask/metamask-extension#36153

## Checklist

- [x] I've updated the test suite for new or updated code as appropriate
- [x] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs),
highlighting breaking changes as necessary
- [ ] I've prepared draft pull requests for clients and consumer
packages to resolve any breaking changes

Author: rarquevaux

packages/transaction-controller/src/TransactionController.test.ts

@@ -5489,6 +5489,55 @@ describe('TransactionController', () => {
         expect(updatedTransaction?.txParams.gasPrice).toBe('0x5678');
         expect(updatedTransaction?.userFeeLevel).toBe('custom');
       });
+
+      it('does not update transaction gas estimates when isAutomaticGasFeeUpdateEnabled returns false', () => {
+        const transactionId = '1';
+
+        const { controller } = setupController({
+          options: {
+            isAutomaticGasFeeUpdateEnabled: () => false,
+            state: {
+              transactions: [
+                {
+                  id: transactionId,
+                  chainId: '0x1',
+                  networkClientId: NETWORK_CLIENT_ID_MOCK,
+                  time: 123456789,
+                  status: TransactionStatus.unapproved as const,
+                  gasFeeEstimates: {
+                    type: GasFeeEstimateType.Legacy,
+                    low: '0x1',
+                    medium: '0x2',
+                    high: '0x3',
+                  },
+                  txParams: {
+                    type: TransactionEnvelopeType.legacy,
+                    from: ACCOUNT_MOCK,
+                    to: ACCOUNT_2_MOCK,
+                    gasPrice: '0x1234',
+                  },
+                },
+              ],
+            },
+          },
+          updateToInitialState: true,
+        });
+
+        controller.updateTransactionGasFees(transactionId, {
+          userFeeLevel: GasFeeEstimateLevel.Medium,
+          gasPrice: '0x5678',
+        });
+
+        expect(updateTransactionGasEstimatesMock).not.toHaveBeenCalled();
+
+        const updatedTransaction = controller.state.transactions.find(
+          ({ id }) => id === transactionId,
+        );
+        expect(updatedTransaction?.txParams.gasPrice).toBe('0x5678');
+        expect(updatedTransaction?.userFeeLevel).toBe(
+          GasFeeEstimateLevel.Medium,
+        );
+      });
     });
   });