Google Drive Loader: The code in the Official Doc does not work; and Setting environment variable GOOGLE_APPLICATION_CREDENTIALS is important, though its value is not
Labels: name: area: doc loader, name: auto:bug

### System Info

Langchain Version - 0.0.348
OS or Platform Version - Windows 11
Python Version - 3.11.5
Conda Version - 23.7.4

### Who can help?

@agola11

### Information

- [X] The official example notebooks/scripts
- [ ] My own modified scripts

### Related Components

- [ ] LLMs/Chat Models
- [ ] Embedding Models
- [ ] Prompts / Prompt Templates / Prompt Selectors
- [ ] Output Parsers
- [X] Document Loaders
- [ ] Vector Stores / Retrievers
- [ ] Memory
- [ ] Agents / Agent Executors
- [ ] Tools / Toolkits
- [ ] Chains
- [ ] Callbacks/Tracing
- [ ] Async

### Reproduction

## BRIEF

* [Issue 1] When using Google Drive Loader to load Google Docs, I encountered several errors following the offcial documentation. I ran my code on 3 different platforms - Windows, Kaggle Notebooks, and CodeSandbox (Linux). [Here is the code](https://python.langchain.com/docs/integrations/document_loaders/google_drive#instructions-for-ingesting-your-google-docs-data) that does not work. 
* [Issue 2] However, after playing with the code for a while, I was able to successfully authenticate with Google and load the docs. But, this brings up another issue to our notice. The environment variable needs to be set, but its value can be any string.

## REPRODUCTION STEPS

<details>
<summary>Pre requisites</summary>

1. Complete the [Prerequisites for the GoogleDriveLoader.](https://python.langchain.com/docs/integrations/document_loaders/google_drive#prerequisites)
2. Create a Google Docs file and copy its document ID. [How to find the document ID.](https://python.langchain.com/docs/integrations/document_loaders/google_drive#instructions-for-ingesting-your-google-docs-data).
3. Please read the section mentioned in point number 2.
4. Create an empty directory on Windows for this issue and place the `credentials.json` file there, recieved from Google Cloud.
5. Create main.py file, to write the below 3 programs, in this directory.
6. I run the program with ```python main.py```

</details>

### FIRST TRY

Follow the documentation

```python
# Set the Path to the credentials and authentication token
credentials_path = "credentials.json"
token_path = "token.json"

# Create the loader object (no environment variable is set)
loader = GoogleDriveLoader(
    document_ids=["Your Document ID here"],
    credentials_path=credentials_path, 
    token_path=token_path
)

# Call the loader, after the above code:
loader.load()
```

<details>
<summary>Output - Errors</summary>

Windows and CodeSandbox (Linux):
> raise exceptions.DefaultCredentialsError(_CLOUD_SDK_MISSING_CREDENTIALS)
google.auth.exceptions.DefaultCredentialsError: Your default credentials were not found. To set up Application Default Credentials, see https://cloud.google.com/docs/authentication/external/set-up-adc for more information.

Kaggle Notebooks:
> RefreshError: Failed to retrieve http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/?recursive=true from the Google Compute Engine metadata service. Compute Engine Metadata server unavailable

</details>

### SECOND TRY

Documentation mentions that if I get RefreshError, I should not pass the credentials path in the constructor, rather in the env var.

```python
# Set the env var. This path was declared before
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = credentials_path # change

loader = GoogleDriveLoader(
    document_ids=["Your Document ID here"],
#    credentials_path=credentials_path, # this one is removed
    token_path=token_path 
)
```

<details>
<summary>Output - Errors</summary>

Kaggle Notebooks and CodeSandbox (Linux)
> FileNotFoundError: [Errno 2] No such file or directory: '/root/.credentials/credentials.json'

Windows
> FileNotFoundError: [Errno 2] No such file or directory: 'C:\\Users\\Username\\.credentials\\credentials.json'
</details>

### THIRD TRY: MY APPROACH

The above error means, if we skip the credentials_path param in the constructor, it uses the default path and does not uses the path provided in the env var.

Now, If I set GOOGLE_APPLICATION_CREDENTIALS environment variable to ANY string and pass the path in the constructor:

```python
os.environ["GOOGLE_APPLICATION_CREDENTIALS"] = "" # change: set the env var to any str
loader = GoogleDriveLoader(
    document_ids=["Your Document ID here"],
    credentials_path=credentials_path, # this one is added again
    token_path=token_path
)
```

<details>
<summary>Output - user authentication to load the gdoc</summary>

Windows and Kaggle Notebook:
> Please visit this URL to authorize this application: https://accounts.google.com/o...

CodeSandbox (Linux) 😂:
> webbrowser.Error: could not locate runnable browser
</details>

## CONCLUSION

* [Issue 1] The code provided in the documentation does not work. A/c to the docs:
  * If the env var is **not set**, and the path is **passed** in the constructor, the code gives errors.
  * If the env var is **set** as the path, and the path is **not passed** in constructor, the code gives errors.

* [Issue 2] The env var needs to be set, but its value is not important. As per my approach:
  * If the env var is **set** as ANYTHING, and the path is **passed** in the constructor, the code works.

### Expected behavior

I do not know what to expect, because the code given in the official documentation is not working correctly.

Suggestion:

However, I would suggest that, if there is no need for the env var, maybe we can remove the step of setting it.

This will resolve the second issue. For first issue, remaining would be to correct the documentation.