### Description

The current length limit for the `login` parameter in an HTTP connection is 500 characters. It'd be nice if this was 5000 characters like the `password` parameter.

### Use case/motivation

We've run into an issue with an API we need to integrate with. It uses basic HTTP authentication, and both username and password are about 900 characters long each. We don't have any control over this API, so we cannot change the authentication method, nor the length of these usernames and passwords.

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

"""
        Verify that ``extra`` is a JSON-encoded Python dict.
        From Airflow 3.0, we should no longer suppress these errors but raise instead.
        """
        if extra is None:
            return None
        try:
            extra_parsed = json.loads(extra)
            if not isinstance(extra_parsed, dict):
                warnings.warn(
                    "Encountered JSON value in `extra` which does not parse as a dictionary in "
                    f"connection {conn_id!r}. From Airflow 3.0, the `extra` field must contain a JSON "
                    "representation of a Python dict.",
                    RemovedInAirflow3Warning,
                    stacklevel=3,
                )
        except json.JSONDecodeError:
            warnings.warn(
                f"Encountered non-JSON in `extra` field for connection {conn_id!r}. Support for "
                "non-JSON `extra` will be removed in Airflow 3.0",
                RemovedInAirflow3Warning,
                stacklevel=2,
            )
        return None
    @reconstructor
    def on_db_load(self):