Relax parameter restriction in claude v2 model (#3591)

Signed-off-by: Sicheng Song <sicheng.song@outlook.com>
(cherry picked from commit 4a33315)

Author: b4sjoo

common/src/main/java/org/opensearch/ml/common/utils/ModelInterfaceUtils.java

@@ -352,9 +352,7 @@ public class ModelInterfaceUtils {
         + "                                    },\n"
         + "                                    \"required\": [\n"
         + "                                        \"type\",\n"
-        + "                                        \"completion\",\n"
-        + "                                        \"stop_reason\",\n"
-        + "                                        \"stop\"\n"
+        + "                                        \"completion\"\n"
         + "                                    ]\n"
         + "                                }\n"
         + "                            },\n"