[fix][broker]Fast return if ack cumulative illegal

[AnonHxy]

Motivation

• It should fast return if ack type is Cumulative with illegal CommandAck

Modifications

• Return if ack.getMessageIdsCount() != 1 or Subscription.isIndividualAckMode(subType)

Verifying this change

• Make sure that the change passes the CI checks.
• Add UT for this case org.apache.pulsar.broker.service.MessageCumulativeAckTest

Documentation

• no-need-doc

[AnonHxy]

/pulsarbot run-failure-checks

[codelipenghui]

The change looks good. Could you please help add a test?

For the changes of line:382, it should be a bug fix and the behavior changed?
Before this change, if cumulative ack happened on a Shared subscription, the ack will take effect, but after this change, the ack will not take effect if the request with only one ack.

pulsar/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentSubscription.java

Lines 373 to 383 in e2fa189

	if (positions.size() != 1) {
	log.warn("[{}][{}] Invalid cumulative ack received with multiple message ids.", topicName, subName);
	return;
	}
	Position position = positions.get(0);
	if (log.isDebugEnabled()) {
	log.debug("[{}][{}] Cumulative ack on {}", topicName, subName, position);
	}
	cursor.asyncMarkDelete(position, mergeCursorProperties(properties),
	markDeleteCallback, previousMarkDeletePosition);

[AnonHxy]

Add UT, PTAL @codelipenghui

[AnonHxy]

/pulsarbot run-failure-checks

[AnonHxy]

/pulsarbot run-failure-checks

[AnonHxy]

/pulsarbot run-failure-checks