2.3: Fix bug with link to widget

[alexislefebvre]

Type

Bugfix

Purpose

Fixes a fatal exception when a link has no widget associated to:

Call to a member function getId() on null

The attachedProperty is nullable:

victoire/Bundle/CoreBundle/Entity/Link.php

Line 76 in 98dba02

* @ORM\JoinColumn(name="attached_widget_id", referencedColumnName="id", onDelete="cascade", nullable=true)

So there's no guarantee than attachedProperty is defined in the context of this PR, hence I added a check in order to avoid the error.

I think that it happened because:

1. a link that pointed to a widget was added
2. the widget was deleted
3. the link lost its attachedProperty and this triggered this error

BC Break

NO