The service annotations.dummy_registry is unregistered with doctrine/annotations v2.

This had the unexpected effect to break the call to addGlobalIgnoredName with doctrine/annotations v2 : #48792 (comment)

By using nullOnInvalid instead of ignoreOnInvalid, the call to addGlobalIgnoredName is restored.

These changes can be tested with this reproducer: https://github.com/alexislefebvre/symfony_bug_app_48792

Downgrading and upgrading doctrine/annotations become possible:

composer require doctrine/annotations:^1.13.0 --with-all-dependencies
composer require doctrine/annotations:^2.0 --with-all-dependencies

Thanks to @derrabus: #48912 (comment)