Repository: langchain
Issue: aindex + Chroma: aindex function fails due to missing delete method implementation
Labels: Ɑ: vector store,🔌: chroma

### Checked other resources

- [X] I added a very descriptive title to this issue.
- [X] I searched the LangChain documentation with the integrated search.
- [X] I used the GitHub search to find a similar question and didn't find it.
- [X] I am sure that this is a bug in LangChain rather than my code.
- [X] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code

```python
from langchain.indexes import SQLRecordManager, aindex
from langchain_community.document_loaders.generic import GenericLoader
from langchain_community.document_loaders.parsers.language.language_parser import LanguageParser
from langchain_ollama import OllamaEmbeddings
from langchain_chroma import Chroma

loader = GenericLoader.from_filesystem(
    dir_path,
    suffixes=[".py"],
    parser=LanguageParser(None, 10),
    show_progress=True,
)
vector_store = Chroma(
    collection_name=collection_name,
    embedding_function=OllamaEmbeddings(model="nomic-embed-text"),
    persist_directory="./chroma_cache",
)
namespace = f"chromadb/{collection_name}"

record_manager = SQLRecordManager(
    namespace,
    db_url="sqlite:///record_manager_cache.sqlite",
)

async def main():
    await record_manager.create_schema()
    results = await aindex(
        docs_source=loader,
        record_manager=record_manager,
        vector_store=vector_store,
        cleanup="incremental",
        source_id_key="source",
    )

    print("done indexing")
    print(results)
    print("-----------------")

asyncio.run(main())

```

### Error Message and Stack Trace (if applicable)

File "/home/artem/.local/lib/python3.12/site-packages/langchain_core/indexing/api.py", line 521, in aindex
    raise ValueError("Vectorstore has not implemented the delete method")
ValueError: Vectorstore has not implemented the delete method

From langchain_core/indexing/api.py
```python
# If it's a vectorstore, let's check if it has the required methods.
    if isinstance(destination, VectorStore):
        # Check that the Vectorstore has required methods implemented
        # Check that the Vectorstore has required methods implemented
        methods = ["adelete", "aadd_documents"]

        for method in methods:
            if not hasattr(destination, method):
                raise ValueError(
                    f"Vectorstore {destination} does not have required method {method}"
                )

        if type(destination).adelete == VectorStore.adelete:
            # Checking if the vectorstore has overridden the default delete method
            # implementation which just raises a NotImplementedError
            raise ValueError("Vectorstore has not implemented the delete method")
```

### Description

I am trying to follow the documentation examples but it seems that `aindex` function is broken. Can someone tell about the correctness of the following check:
```python
  if type(destination).adelete == VectorStore.adelete:
            # Checking if the vectorstore has overridden the default delete method
            # implementation which just raises a NotImplementedError
            raise ValueError("Vectorstore has not implemented the delete method")
```

How is that supposed to work with langchain_chroma ?
It works just fine with index and doesn't want to work with aindex 

### System Info

$ python -m langchain_core.sys_info

System Information
------------------
> OS:  Linux
> OS Version:  #45-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug 30 12:02:04 UTC 2024
> Python Version:  3.12.3 | packaged by conda-forge | (main, Apr 15 2024, 18:38:13) [GCC 12.3.0]

Package Information
-------------------
> langchain_core: 0.3.6
> langchain: 0.3.1
> langchain_community: 0.3.1
> langsmith: 0.1.128
> langchain_chroma: 0.1.4
> langchain_ollama: 0.2.0
> langchain_text_splitters: 0.3.0
> langgraph: 0.2.34
> langserve: 0.3.0

Other Dependencies
------------------
> aiohttp: 3.10.5
> async-timeout: 4.0.3
> chromadb: 0.5.11
> dataclasses-json: 0.6.7
> fastapi: 0.115.0
> httpx: 0.27.2
> jsonpatch: 1.33
> langgraph-checkpoint: 2.0.1
> numpy: 1.26.4
> ollama: 0.3.3
> orjson: 3.10.7
> packaging: 24.1
> pydantic: 2.9.2
> pydantic-settings: 2.5.2
> PyYAML: 6.0.2
> requests: 2.32.3
> SQLAlchemy: 2.0.35
> sse-starlette: 1.8.2
> tenacity: 8.5.0
> typing-extensions: 4.12.2