fix: be consistent in regexp for props matching (openfoodfacts#10579)

A very simple fix to have consistent regexp with next line

lib/ProductOpener/Tags.pm

@@ -1521,7 +1521,7 @@ sub build_tags_taxonomy ($tagtype, $publish) {
 					push(@taxonomy_errors, _taxonomy_error("ERROR", "unknown_nutriscore", $msg, $line_number));
 				}
 			}
-			elsif ($line =~ /^expected_ingredients:en:/) {
+			elsif ($line =~ /^expected_ingredients:en: */) {
 				# the line should contain a single ingredient
 				my $expected_ingredients = $';    # everything after the matched string