Warning: Constant MAX_ITEMS already defined in include_once()

Warning: Constant MAX_ITEMS already defined in include_once() (line 8 of sites/domain.com/files/civicrm/ext/fromemailpermission/fromemailpermission.php).
Warning: Constant MAX_ITEMS already defined in include_once() (line 8 of sites/domain.com/files/civicrm/ext/fromemailpermission/fromemailpermission.php).

Source: https://lab.civicrm.org/extensions/fromemailpermission/-/blob/1.1.3/fromemailpermission.php?ref_type=tags#L8

cc: @sluc23