fix: unable to reindex documents (#5276)

api/core/rag/datasource/vdb/weaviate/weaviate_vector.py

         schema = self._default_schema(self._collection_name)
         if self._client.schema.contains(schema):
             for uuid in ids:
-                self._client.data_object.delete(
-                    class_name=self._collection_name,
-                    uuid=uuid,
-                )
+                try:
+                    self._client.data_object.delete(
+                        class_name=self._collection_name,
+                        uuid=uuid,
+                    )
+                except weaviate.UnexpectedStatusCodeException as e:
+                    # tolerate not found error
+                    if e.status_code != 404:
+                        raise e
 
     def search_by_vector(self, query_vector: list[float], **kwargs: Any) -> list[Document]:
         """Look up similar documents by embedding vector in Weaviate."""