fix: correctly allow to load from a databased setup with subindices

[samsja]

context

ATM we could not read from a database which has been setup with sub indices. This pr fix this (original issue here )

from docarray import Document, DocumentArray, dataclass
from docarray.typing import Image, Text

@dataclass
class MyDocument:
    image: Image
    paragraph: Text

# extend with Documents, including embeddings
_docs = [(MyDocument( image='https://docarray.jina.ai/_images/apple.png', paragraph='hello world'))]

da = DocumentArray(
    storage='sqlite',  # use SQLite as vector database
    config={'connection': 'jina4.db', 'table_name': 'test4'},
    subindex_configs={'@.[image]': {'connection': 'jina4.db', 'table_name': 'test5'}, '@.[paragraph]': {'connection': 'jina4.db', 'table_name': 'test6'}},  # set up subindices for image and description
)
da.summary()

for item in _docs:
  d = Document(item)
  da.append(d)

da = DocumentArray(
    storage='sqlite',  # use SQLite as vector database
    config={'connection': 'jina4.db', 'table_name': 'test4'},
    subindex_configs={'@.[image]': {'connection': 'jina4.db', 'table_name': 'test5'}, '@.[paragraph]': {'connection': 'jina4.db', 'table_name': 'test6'}},  # set up subindices for image and description
)
da.summary()

This will now work