Fix s3 folder scan depth for RDS source when partition prefix is not set

Author: divbok

data-prepper-pipeline-parser/src/main/java/org/opensearch/dataprepper/pipeline/parser/transformer/DynamicConfigTransformer.java

@@ -433,7 +433,9 @@ public String calculateDepth(String s3Prefix) {
      * @return s3 folder scan depth
      */
     public String calculateDepthForRdsSource(String s3Prefix) {
-        return Integer.toString(getDepth(s3Prefix, 3));
+        String envSourceCoordinationIdentifier = System.getenv(SOURCE_COORDINATION_IDENTIFIER_ENVIRONMENT_VARIABLE);
+        int baseDepth = envSourceCoordinationIdentifier != null ? 3 : 2;
+        return Integer.toString(getDepth(s3Prefix, baseDepth));
     }
 
     private int getDepth(String s3Prefix, int baseDepth) {