Extra fields added to all entity types, causing noise in exported config

I also need the same feature (option to limit entity print to some specified types). I also discovered that extra fields are added to every single entity type, not just to content entity types.

Changing the category to feature request.

* Added a new config option to restrict print features to entity types.
* Added a config subscriber which resets entity field caches if config value is changed
* Updated hook implementations
* Added test coverage

Asking for review.

Now I can limit entity print only to a limited group of entity types. No more unneeded extra fields and a huge Git diff on config export. Code looks good. Apart from manual testing, I see it has solid test coverage.

We just hit an error with this patch applied, checking what's going on (should be obvious imho):

php.WARNING: Warning: Undefined array key "webform_submission" in entity_print_entity_extra_field_info() (line 63 of <project-root>/web/modules/contrib/entity_print/entity_print.module)

Moving back to NW.

Th test method I just added should reveal the problem we saw (see #6)

There they are!

https://git.drupalcode.org/issue/entity_print-3468563/-/jobs/3536971#L127

1 test triggered 2 PHP warnings:
1) /builds/issue/entity_print-3468563/entity_print.module:63
Undefined array key "entity_test_with_bundle"
Triggered by:
* Drupal\Tests\entity_print\Kernel\ExtraFieldsTest::testBundleableEntityTypeWithoutBundle
  /builds/issue/entity_print-3468563/tests/src/Kernel/ExtraFieldsTest.php:192
2) /builds/issue/entity_print-3468563/entity_print.module:63
foreach() argument must be of type array|object, null given
Triggered by:
* Drupal\Tests\entity_print\Kernel\ExtraFieldsTest::testBundleableEntityTypeWithoutBundle
  /builds/issue/entity_print-3468563/tests/src/Kernel/ExtraFieldsTest.php:192
OK, but there were issues!
Tests: 59, Assertions: 544, Warnings: 2.

I hope we can get back the RTBC status 🥹

Looks good, moving to RTBC.