Issue #3587305: TypeError: SectionComponent additional argument must be array,...
Fixes #3587305.
DashboardStorageHandler::mapFromStorageRecords() passes
$component['additional'] directly to the SectionComponent constructor.
When that key is stored as NULL in existing configuration, PHP 8 enforces
the strict array type hint and throws a fatal TypeError, taking down the
entire site.
The fix uses the null coalescing operator (?? []) to fall back to an empty
array, matching the same defensive pattern used by Drupal core's
Section::fromArray().
Edited by Álvaro Olvera Fernández