Personal agenda still available in agenda_js.php when allow_personal_agenda set to false

[ywarnier]

The settings_current option "allow_personal_agenda" is old and still removes the PHP "action bar" icons allowing users to add personal agenda events, but does not block the user from adding personal events when clicking the JS calendar.

This is a bug. It has to be fixed by checking if allow_personal_agenda is true before allowing a modal to emerge and create a new event.

Tested in 1.11.x 2023-06-06.