[DOCS] Replace the FF image at the bottom of Product Docs > Issues page

[ryan953]

At the bottom of this page there's an image of FF Change Tracking annotations ontop of the Event Volume chart.

The image could be better.

We could find an example where the Event Volume is smoother, and maybe has a start date within the visible time range. Then if there is a FF that is suspicious (was changed right before the issue started) it would stand out better and be more illustrative to users that this is a great feature for quickly fixing new regressions.