Don't show additional info / steps to repro if empty

The print issue page was showing these fields when empty, which is inconsistent
with the view issue page.

Fixes #20600

print_bug_page.php

@@ -121,8 +121,8 @@
 $t_show_target_version = $t_show_versions && in_array( 'target_version', $t_fields ) && access_has_bug_level( config_get( 'roadmap_view_threshold' ), $f_bug_id );
 $t_show_summary = in_array( 'summary', $t_fields );
 $t_show_description = in_array( 'description', $t_fields );
-$t_show_steps_to_reproduce = in_array( 'steps_to_reproduce', $t_fields );
-$t_show_additional_information = in_array( 'additional_info', $t_fields );
+$t_show_steps_to_reproduce = !is_blank( $t_bug->steps_to_reproduce ) && in_array( 'steps_to_reproduce', $t_fields );
+$t_show_additional_information = !is_blank( $t_bug->additional_information ) && in_array( 'additional_info', $t_fields );
 $t_show_tags = in_array( 'tags', $t_fields );
 $t_show_attachments = in_array( 'attachments', $t_fields );
 $t_show_history = access_has_bug_level( config_get( 'view_history_threshold' ), $f_bug_id );