Fix handling of JMS listener concurrency properties

Update JMS listener concurrency configuration to set the same minimum
and maximum number of consumers when users specify only the minimum
using `spring.jms.listener.concurrency` property.

Prior to this commit, when using `spring.jms.listener.concurrency` to
set the minimum number of consumers without also specifying
`spring.jms.listener.max-concurrency` would result in effective
concurrency where the actual minimum number of consumers is always 1,
while the maximum number of consumers is the value of
`spring.jms.listener.concurrency`.

See gh-37180

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jms/JmsProperties.java

@@ -198,8 +198,7 @@ public String formatConcurrency() {
 			if (this.concurrency == null) {
 				return (this.maxConcurrency != null) ? "1-" + this.maxConcurrency : null;
 			}
-			return ((this.maxConcurrency != null) ? this.concurrency + "-" + this.maxConcurrency
-					: String.valueOf(this.concurrency));
+			return this.concurrency + "-" + ((this.maxConcurrency != null) ? this.maxConcurrency : this.concurrency);
 		}
 
 		public Duration getReceiveTimeout() {

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jms/JmsPropertiesTests.java

@@ -41,7 +41,7 @@ void formatConcurrencyNull() {
 	void formatConcurrencyOnlyLowerBound() {
 		JmsProperties properties = new JmsProperties();
 		properties.getListener().setConcurrency(2);
-		assertThat(properties.getListener().formatConcurrency()).isEqualTo("2");
+		assertThat(properties.getListener().formatConcurrency()).isEqualTo("2-2");
 	}
 
 	@Test