Update ExportGroup.php: remove facility access related fields

[lucix-mich]

Facility access seems to be a leftover from features now removed. Remove the two fields from the contacts export function.

I have:

• [*] tested this doesn't break the export function, and that the result is what is expected
• ensured unit tests all run without error
• ran psalm and corrected any static analysis issues
• ensured all relevant template output is escaped to avoid XSS attached with <?= $t->ee( $data ) ?> or equivalent
• ensured appropriate checks against user privilege / resources accessed
• API calls (particular for add/edit/delete/toggle) are not implemented with GET and use CSRF tokens to avoid CSRF attacks