Poll the engine_exchangeTransitionConfigurationV1 endpoint (#3047)

## Issue Addressed

There has been an [`engine_exchangetransitionconfigurationv1`](https://github.com/ethereum/execution-apis/blob/main/src/engine/specification.md#engine_exchangetransitionconfigurationv1) method added to the execution API specs.

The `engine_exchangetransitionconfigurationv1` will be polled every 60s as per this PR: https://github.com/ethereum/execution-apis/pull/189. If that PR is merged as-is, then we will be matching the spec. If that PR *is not* merged, we are still fully compatible with the spec, but just doing more than we are required.

## Additional Info

- [x] ~~Blocked on #2837~~
- [x] Add method to EE integration tests

testing/execution_engine_integration/src/test_rig.rs

@@ -108,6 +108,16 @@ impl<E: GenericExecutionEngine> TestRig<E> {
     pub async fn perform_tests(&self) {
         self.wait_until_synced().await;
 
+        /*
+         * Check the transition config endpoint.
+         */
+        for ee in [&self.ee_a, &self.ee_b] {
+            ee.execution_layer
+                .exchange_transition_configuration(&self.spec)
+                .await
+                .unwrap();
+        }
+
         /*
          * Read the terminal block hash from both pairs, check it's equal.
          */