refactor(clear): simplify clear() with async iterator + pipeline

[JH8459]

Summary

I'm using this library in a production project — it has been very helpful, thanks for maintaining it! 🙏
While reviewing the internal implementation, I found the clear() method a bit hard to follow because it mixed Promise construction and event callbacks.

This PR refactors clear() to use a modern async iterator pattern (for await...of) with batched pipeline deletion,
making the flow easier to read and maintain without changing the behavior.

---

Changes

• Simplified clear() by replacing manual Promise and stream.on(...) callbacks with for await...of.
• Each SCAN batch is deleted through pipeline.del() followed by pipeline.exec().
• No changes to the method signature or functionality.

---

Why

The previous version worked fine but relied on nested callbacks and explicit Promise construction,
which made it less straightforward to read.
Using async iteration improves readability and aligns with modern Node.js async I/O practices.

---

Notes

• Tested with Redis v7.2 and Node 22.
• No breaking changes.
• This PR focuses purely on internal readability and maintainability improvements.

Thanks again for the great library!

[ramiel]

Thanks. Yes, definitely more readable. Some log messages are now missing but I can put them back later

[ramiel]

Available in new version 4.0.1