#4152 Changed gantt chart tooltip location

[AbhinavGonthina]

Changes

Updated tooltip positioning on the Gantt chart so it follows where the user hovers instead of appearing in a fixed spot.

It now uses the mouse coordinates from the hover event and places the tooltip near the cursor.

Notes

I added an x coordinate prop into GanttTooltipProps such that the tooltip now is close to the user's cursor when they hover over a gantt chart element. I also changed the y coordinate calculation and variable declarations for better code readability and visibility.

Also, it seems that gantt elements which have subelements have the tooltip positions where the start of the sub element which is being hovered over is, but this is not a huge difference than what may be expected in my opinion.

Screenshots

Gantt.Chart.Tooltips.mp4

To Do

Change positioning of tooltip if needed.

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Closes #4152