Remove prototype files (#6830)

* Remove prototype files

 - Remove the original prototype files for the message manager in
   services/sns
 - Remove the kiro hooks not intended for release with the sns message
   manager

* Update version in POM

Parent version changed after merge from master

Author: dagnir

.kiro/hooks/aws-sdk-code-review.kiro.hook

@@ -21,7 +21,7 @@
     <parent>
         <groupId>software.amazon.awssdk</groupId>
         <artifactId>aws-sdk-java-pom</artifactId>
-        <version>2.42.15-SNAPSHOT</version>
+        <version>2.42.25-SNAPSHOT</version>
         <relativePath>../../pom.xml</relativePath>
     </parent>
     <artifactId>sns-message-manager</artifactId>