Add mouse wheel zoom support for Y-axis

[ashutosh-trader]

Summary

Add support for zooming the Y-axis using the mouse wheel, allowing users to quickly adjust the vertical scale without dragging.

Changes

• Add mouse wheel zoom handling for Y-axis widget in mouseWheelVertEvent
• Extract Y-axis zoom logic into reusable _zoomYAxis private method
• Reuse the same zoom logic for both drag-to-scale and scroll-to-zoom interactions

Behavior

When the mouse is over the Y-axis and scrollZoomEnabled is true:

• Scrolling up zooms in (decreases range)
• Scrolling down zooms out (increases range)

This matches the existing zoom behavior on the main chart area and provides a more intuitive way to adjust the Y-axis scale.

[ashutosh-trader]

closed PR #787 to add mouse wheel / touch scroll support

[ashutosh-trader]

@liihuu please review this , I have tested this to be working fine using both mousewheel and touchbar