Public symbols not properly exported with `py.typed` present — triggers Pylance/Pyright errors

Hi team,

Thanks for maintaining this package — it's a great tool for working with InfluxDB.

I'm opening this issue to report a problem that affects type checkers and IDEs (like Pyright, Pylance, and mypy) due to the presence of the `py.typed` file in the `influxdb-client-python` package.

Since the package declares itself as typed (via `py.typed`, per [[PEP 561](https://peps.python.org/pep-0561/)](https://peps.python.org/pep-0561/)), tools like **Pyright** and **Pylance** apply stricter rules around public API exposure. Specifically, **public symbols must be explicitly exported** using either:

* a `__all__` list in `__init__.py`, or
* `.pyi` stub files.

Currently, this is not the case for the main client class. When importing `InfluxDBClient` from the top-level module as documented:

```python
from influxdb_client import InfluxDBClient
```

Pylance (and Pyright) raises the following error:

```
"InfluxDBClient" is not exported from module "influxdb_client"
Import from "influxdb_client.client.influxdb_client" instead
Pylance: reportPrivateImportUsage
```

This is confusing to users and suggests that the public API is not properly defined.

### Suggested solutions

To resolve this and ensure compatibility with type checkers, here are a few possible approaches:

1. **Add `__all__` to `influxdb_client/__init__.py`** to explicitly define the intended public interface.
2. **Provide proper `.pyi` stub files** that describe the public API.
3. If full typing support is not maintained, **consider removing the `py.typed` file** to avoid stricter validation.

Improving this would help developers relying on static analysis and IDE support, and reduce confusion about which imports are officially supported.

Thanks again for your work and for considering this issue!

Beginne mit der Untersuchung von influxdb_client/__init__.py und dem py.typed-Marker des Pakets und reproduziere anschließend den dokumentierten Import `from influxdb_client import InfluxDBClient` mit Pyright oder Pylance. Ermittle die vorgesehenen öffentlichen Exporte und überprüfe, dass der Import auf oberster Ebene nicht mehr die gemeldete Diagnose zu einem privaten Import erzeugt.

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