Calculate user bounds when 'getMinMax()' is called

[Cowjiang]

In the Financial Chart, thx y-axis remains unchanged when I use chatjs-plugin-zoom to zoom in. That's because the FinancialController overrides the method 'getMinMax()' and it doesn't calculate the range of data points which in user bounds.

So I add a method to get min/max values by scale.getUserBounds() and a filter for parsedDatas.