Refactor: Replace inline onclick handler with addEventListener in 'dashboard_html.py'

[pyob-bot]

Summary of Changes

This PR modifies the dashboard_html.py file to enhance the event handling mechanism for the 'moveDownBtn' button. Specifically, it replaces the inline onclick handler with the addEventListener method. This adjustment is aligned with best practices for JavaScript event handling which promote better separation of concerns and code scalability.

Technical Impact

• Enhanced Maintainability: By using addEventListener, the code becomes easier to maintain and extend. This method allows multiple event listeners to be added to a single DOM element, providing greater flexibility.
• Better Separation of Concerns: Moving the event handling logic away from the HTML/DOM structure aids in separating the structural code from the behavior, making it cleaner and more modular.
• Scalability: This change sets a precedent for using addEventListener in future feature implementations where multiple event listeners might be necessary on the same element.

No new functionality has been added; this change solely refactors the event handling mechanism for improved code quality.