mixup in case of DISPLAY messages type

[cstamas]

ProjectEvent message mixup fixed.

Fixes #1036

[gnodet]

It's wrong imho.
The type of message identifies how it will be read, see

maven-mvnd/common/src/main/java/org/mvndaemon/mvnd/common/Message.java

Lines 80 to 123 in 2b8076d

	case BUILD_REQUEST:
	return BuildRequest.read(input);
	case BUILD_STARTED:
	return BuildStarted.read(input);
	case BUILD_FINISHED:
	return BuildFinished.read(input);
	case MOJO_STARTED:
	return MojoStartedEvent.read(input);
	case PROJECT_LOG_MESSAGE:
	case DISPLAY:
	return ProjectEvent.read(type, input);
	case BUILD_EXCEPTION:
	return BuildException.read(input);
	case KEEP_ALIVE:
	return BareMessage.KEEP_ALIVE_SINGLETON;
	case STOP:
	return BareMessage.STOP_SINGLETON;
	case PROMPT:
	return Prompt.read(input);
	case PROMPT_RESPONSE:
	return PromptResponse.read(input);
	case PROJECT_STARTED:
	case PROJECT_STOPPED:
	case BUILD_STATUS:
	case BUILD_LOG_MESSAGE:
	return StringMessage.read(type, input);
	case CANCEL_BUILD:
	return BareMessage.CANCEL_BUILD_SINGLETON;
	case TRANSFER_INITIATED:
	case TRANSFER_STARTED:
	case TRANSFER_PROGRESSED:
	case TRANSFER_CORRUPTED:
	case TRANSFER_SUCCEEDED:
	case TRANSFER_FAILED:
	return TransferEvent.read(type, input);
	case EXECUTION_FAILURE:
	return ExecutionFailureEvent.read(input);
	case PRINT_OUT:
	case PRINT_ERR:
	return StringMessage.read(type, input);
	case REQUEST_INPUT:
	return RequestInput.read(input);
	case INPUT_DATA:
	return InputData.read(input);

So we can't have two message classes for the same message type.