AutowireTrait and autowire for services behave differently for nullable types

I ran into this exact issue when dealing with an optional dependency. The suggested solution makes sense to me.

I added the test.

1) Drupal\KernelTests\Core\DependencyInjection\AutowireTest::testAutowireInvalidDependency
Symfony\Component\DependencyInjection\Exception\AutowiringFailedException: Cannot autowire service "Drupal\KernelTests\Core\DependencyInjection\InvalidServiceInterface": argument "$service" of method "Drupal\KernelTests\Core\DependencyInjection\InvalidOptionalDependencyController::_construct()", you should configure its value explicitly.
/builds/issue/drupal-3464426/core/lib/Drupal/Core/DependencyInjection/AutowireTrait.php:37
/builds/issue/drupal-3464426/core/tests/Drupal/KernelTests/Core/DependencyInjection/AutowireTest.php:191
ERRORS!
Tests: 4, Assertions: 7, Errors: 1.

Seems like good test coverage