Don’t indent column headings if no row errors

The reason to indent the first column heading is so that the number 1
lines up with the numbers of subsequent rows.

This only happens when the subsequent rows are indented because of the
red bars. This is only when there are row errors, not when there are
more general errors.

app/templates/views/check/column-errors.html

@@ -107,7 +107,7 @@
       caption=original_file_name,
       caption_visible=False,
       field_headings=[
-        '<span class="visually-hidden">Row in file</span><span aria-hidden="true" class="{}">1</span>'.format("table-field-invisible-error" if errors else "")|safe
+        '<span class="visually-hidden">Row in file</span><span aria-hidden="true">1</span>'|safe
       ] + recipients.column_headers
     ) %}
       {% call index_field() %}