text: Title: Bug: Equality of DocVec
  Body: Equality between instances of DocVec does not seem to work properly:
  
  ```python
  from docarray import BaseDoc, DocList
  
  
  class CustomDocument(BaseDoc):
      image: str
  
  
  da = DocList[CustomDocument](
      [CustomDocument(image='hi') for _ in range(10)]
  ).to_doc_vec()
  
  da2 = DocList[CustomDocument](
      [CustomDocument(image='hi') for _ in range(10)]
  ).to_doc_vec()
  
  print(da == da2)
  ```
  ```bash
  False
  ```