Ignore trailing comments when splitting SQL batches

A comment after the last semicolon ("SELECT 1; -- note") became a
statement of its own. It is not a read, so the whole batch asked for
confirmation and the comment was then sent to the database. Drop parts
that contain only comments.

lib/Service/SqlGuard.php

@@ -87,8 +87,9 @@ class SqlGuard
 
         $statements[] = trim($current);
 
+        // A trailing comment ("SELECT 1; -- note") is not a statement
         return array_values(array_filter($statements, function ($s) {
-            return $s !== '';
+            return trim(self::removeComments($s)) !== '';
         }));
     }