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

[barryo]

Thanks @lucix-mich - I'll add a migration to clean the database also in main.

[lucix-mich]

Thanks!
I hope whoever uses this will not depend on the exact fields in the generated output, or this might break things.
On the other hand, being able to select fields to export would be a worthwhile improvement to avoid breaking changes going further.