style: add a space

Author: php-coder

src/main/resources/sql/collection_dao_queries.properties

@@ -22,7 +22,7 @@ collection.find_series_by_collection_id = \
            SELECT COUNT(*) \
              FROM series_images si \
             WHERE si.series_id = s.id \
-              AND si.hidden = FALSE\
+              AND si.hidden = FALSE \
           ) AS number_of_images \
         , ( \
              SELECT si.image_id \