Prevent rabbitmq starter to bring webflux on the classpath

This commit excludes `com.rabbitmq:http-client` from `spring-rabbit` as
the former brings spring webflux for an optional feature. This also
prevents Spring Boot to consider that a web server should be started as
all the necessary pieces are unexpectedly present.

Closes gh-12853

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -2574,6 +2574,12 @@
 				<groupId>org.springframework.amqp</groupId>
 				<artifactId>spring-rabbit</artifactId>
 				<version>${spring-amqp.version}</version>
+				<exclusions>
+					<exclusion>
+						<groupId>com.rabbitmq</groupId>
+						<artifactId>http-client</artifactId>
+					</exclusion>
+				</exclusions>
 			</dependency>
 			<dependency>
 				<groupId>org.springframework.amqp</groupId>