Fix regression in JmsAccessor#setSessionAcknowledgeMode

This commit partially reverts 3b8dd0a5, which introduced a strict
validation in JmsAccessor#setSessionAcknowledgeMode that prevents use
of vendor-specific acknowledge modes.

See gh-31328

spring-jms/src/main/java/org/springframework/jms/support/JmsAccessor.java

@@ -167,8 +167,6 @@ public abstract class JmsAccessor implements InitializingBean {
 	 * @see jakarta.jms.Connection#createSession(boolean, int)
 	 */
 	public void setSessionAcknowledgeMode(int sessionAcknowledgeMode) {
-		Assert.isTrue(sessionConstants.containsValue(sessionAcknowledgeMode),
-				"Only values of acknowledge mode constants allowed");
 		this.sessionAcknowledgeMode = sessionAcknowledgeMode;
 	}