fix(sqdataset): add missing pragma once to header (#212)

Author: ahuber21

include/svs/extensions/vamana/scalar.h

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#pragma once
+
 #include "svs/index/vamana/extensions.h"
 #include "svs/quantization/scalar/scalar.h"