Excel batch completely fails if style is given in default display

Problem/Motivation

I upgraded to PHP 8, Drupal 9 and whatnot. Now my Excel exports bomb.

Steps to reproduce

I attached the view but the point is, if the style is configured in the default display and not the overridden data export display then the options are simply not there.

Proposed resolution

The patch attached works -- and after writing it I found line 802 and 807 uses the same code which gives me some confidence. Is it time for a helper method? ksenzee taught me to factor out things used three times :)

drush php has this to say:

>>> $view->getStyle()->options['formats'];
=> [
     "xlsx" => "xlsx",
   ]
>>> $view->getDisplay()->options['style']
=> [
     "type" => "data_export",
     "options" => [],
   ]

Remaining tasks

User interface changes

API changes

Data model changes