HubConnection.on() can't take primitive classes in Java

[wtgodbe]

Followup to #21644 and #23532

The .on() methods in HubProtocol should handle primitive classes the same way that .invoke() does:

aspnetcore/src/SignalR/clients/java/signalr/src/main/java/com/microsoft/signalr/HubConnection.java

Lines 699 to 704 in 4ecde5f

	// Primitive types can't be cast with the Class cast function
	if (returnType.isPrimitive()) {
	subject.onSuccess((T)result);
	} else {
	subject.onSuccess(returnType.cast(result));
	}

[wtgodbe]

Fixed by #25773