Initialize default collection property rule does not work on php attribute

[aszenz]

Rule:
https://github.com/rectorphp/rector-doctrine/blob/main/docs/rector_rules_overview.md#initializedefaultentitycollectionrector

Reproducer:

https://getrector.org/demo/1ec78515-bc82-6f9a-a506-77d427391643

[aszenz]

Failing fixture : aszenz:patch-4

[TomasVotruba]

I've cherry picked the test in #80, thank you 👍