Fixed deprecation message for InlineConstraint always displayed

[jorrit]

Subject

I noticed that the following deprecation message was displayed all the time, even when the deprecated class wasn't called:

User Deprecated: The Sonata\CoreBundle\Validator\Constraints\InlineConstraint class is deprecated since version 3.13.0 and will be removed in 4.0. Use Sonata\Form\Validator\Constraint\InlineConstraint instead.

The reason is a small omission in the code. The following line:

if (!class_exists(Sonata\Form\Validator\Constraints\InlineConstraint::class, false)) {

should have been:

if (!class_exists(\Sonata\Form\Validator\Constraints\InlineConstraint::class, false)) {

The InlineConstraint class is the only class with this bug, all the other deprecated classes work correctly in this respect.

I am targeting this branch, because it's a backwards compatible change.

Changelog

### Fixed
- Deprecation message for InlineConstraint was always displayed

[jorrit]

The items found by FlintCI are not related to this PR.

[core23]

The items found by FlintCI are not related to this PR.

Also they are not related, can you fix them and create a new PR for this? Otherwise we cannot merge this.

[jorrit]

@core23 I think I based the PR on a wrong commit because the problems found by FlintCI disappeared after I rebased the commit.

[jordisala1991]

Thank you @jorrit !