PR: Add 'qtwait' function to 'qthelpers' module

[jnsebgosselin]

This PR introduces a new utility function, qtwait, to the qthelpers module.

Key features:

• The qtwait function provides a convenient way to block execution within a Qt event loop until a specified condition becomes true, or a timeout occurs.
• The function supports checking the condition at a configurable interval, custom timeout durations, and custom error messages on timeout.
• This is useful for synchronizing asynchronous events in Qt-based applications and for writing robust tests with frameworks such as pytest-qt.

Why?

• Helps manage asynchronous event synchronization in a clean and reliable way.
• Facilitates writing and maintaining tests for Qt code that depend on timing or external events.