Start building against Spring AMQP 2.4.6 snapshots

See gh-31376

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -1650,7 +1650,7 @@ bom {
 			]
 		}
 	}
-	library("Spring AMQP", "2.4.5") {
+	library("Spring AMQP", "2.4.6-SNAPSHOT") {
 		prohibit("[3.0.0-M1,)") {
 			because "it uses Spring Framework 6"
 		}