Reset function for VectorDBs (#2584)

mem0/vector_stores/opensearch.py

@@ -199,3 +199,9 @@ class OpenSearchDB(VectorStoreBase):
                 for hit in response["hits"]["hits"]
             ]
         ]
+        
+    def reset(self):
+        """Reset the index by deleting and recreating it."""
+        logger.warning(f"Resetting index {self.collection_name}...")
+        self.delete_col()
+        self.create_index()