Update to spring-cloud-function 4.2.1

This updates spring-cloud-function to 4.2.1 in order
to pickup spring-cloud/spring-cloud-function#1224
which brings the fix for functions declared as `FactoryBean`.

stream-applications-build/pom.xml

@@ -38,12 +38,12 @@
         <spring-boot.version>3.4.2-SNAPSHOT</spring-boot.version>
         <spring-cloud.version>2024.0.0</spring-cloud.version>
         <!-- SC bom override to pickup spring-cloud/spring-cloud-function#1224 -->
-        <spring-cloud-function.version>4.2.1-SNAPSHOT</spring-cloud-function.version>
+        <spring-cloud-function.version>4.2.1</spring-cloud-function.version>
         <!-- =================================================================== -->
         <!-- Required only for release train docs generation in -->
         <!-- /stream-applications-release-train/stream-applications-docs/pom.xml -->
         <spring.version>6.2.1</spring.version>
-        <spring-cloud-stream-dependencies.version>4.2.1-SNAPSHOT</spring-cloud-stream-dependencies.version>
+        <spring-cloud-stream-dependencies.version>4.2.0</spring-cloud-stream-dependencies.version>
         <!-- =================================================================== -->
         <mockserver.version>5.15.0</mockserver.version>
         <apache-ivy.version>2.5.2</apache-ivy.version>