support bwc for process function (opensearch-project#1427) (opensearc…

…h-project#1439)

* support bwc for process function

Signed-off-by: Yaliang Wu <ylwu@amazon.com>

* add comment

Signed-off-by: Yaliang Wu <ylwu@amazon.com>

---------

Signed-off-by: Yaliang Wu <ylwu@amazon.com>
(cherry picked from commit efe5566)

Co-authored-by: Yaliang Wu <ylwu@amazon.com>
Signed-off-by: TrungBui59 <bui23@purdue.edu>

ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/remote/ConnectorUtils.java

@@ -94,7 +94,10 @@ private static RemoteInferenceInputDataSet processTextDocsInput(TextDocsInputDat
             List<String> docs = new ArrayList<>();
             for (String doc : inputDataSet.getDocs()) {
                 if (doc != null) {
-                    docs.add(gson.toJson(doc));
+                    String gsonString = gson.toJson(doc);
+                    // in 2.9, user will add  " before and after string
+                    // gson.toString(string) will add extra " before after string, so need to remove
+                    docs.add(gsonString.substring(1, gsonString.length() - 1));
                 } else {
                     docs.add(null);
                 }