allow FieldConfigInterface::setDefaultValueCallback() to accept a callback in service notation

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Fixing attribution

New MR on 11.x using the new callable resolver service.

for the CC failure

Fixed.

for CC failure.

Not sure if the failure is relevant to this issue but can't rerun so MR may need to be updated.

Rebased.

Still seems to have a test failure.

The test is failing because the callback is not behaving in the same way.

This code in the test + some dumping:

    $entity = EntityTest::create([
      'field_test_file' => [
        'entity' => $file,
      ],
    ]);

    dump('owner ID in test');
    dump($file->getOwnerId());

On 11.x, getOwnerId() is NULL. On the MR, it's 0.

I think we're actually fixing a bug here. The entity owner shouldn't ever be NULL because EntityOwnerTrait::getDefaultEntityOwner() returns the current user.

Any ideas how that is happening? I feel it's not a rabbithole we should go down -- rather we should fix the test, as it seems to me that currently it's only passing by accident.