eth/catalyst: fix error message in ExecuteStatelessPayloadV4 (#32269)

Correct the error message in the ExecuteStatelessPayloadV4 function to
reference newPayloadV4 and the Prague fork, instead of incorrectly
referencing newPayloadV3 and Cancun. 

This improves clarity during debugging and aligns the error message with 
the actual function and fork being validated. No logic is changed.

---------

Co-authored-by: rjl493456442 <[email protected]>

Author: Galoretka

eth/catalyst/witness.go

@@ -228,8 +228,8 @@ func (api *ConsensusAPI) ExecuteStatelessPayloadV4(params engine.ExecutableData,
 		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil beaconRoot post-cancun")
 	case executionRequests == nil:
 		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, paramsErr("nil executionRequests post-prague")
-	case !api.checkFork(params.Timestamp, forks.Prague):
-		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, unsupportedForkErr("newPayloadV3 must only be called for cancun payloads")
+	case !api.checkFork(params.Timestamp, forks.Prague, forks.Osaka):
+		return engine.StatelessPayloadStatusV1{Status: engine.INVALID}, unsupportedForkErr("newPayloadV4 must only be called for prague payloads")
 	}
 	requests := convertRequests(executionRequests)
 	if err := validateRequests(requests); err != nil {