unistore: save returns a writecloser (#107955)

* unistore: save returns a writecloser

* go-lint

* address comments

pkg/storage/unified/resource/datastore.go

@@ -247,7 +247,17 @@ func (d *dataStore) Save(ctx context.Context, key DataKey, value io.Reader) erro
 		return fmt.Errorf("invalid data key: %w", err)
 	}
 
-	return d.kv.Save(ctx, dataSection, key.String(), value)
+	writer, err := d.kv.Save(ctx, dataSection, key.String())
+	if err != nil {
+		return err
+	}
+	_, err = io.Copy(writer, value)
+	if err != nil {
+		_ = writer.Close()
+		return err
+	}
+
+	return writer.Close()
 }
 
 func (d *dataStore) Delete(ctx context.Context, key DataKey) error {