Modify P-value filter in a LocusZoom plot to take an actual P-value as the input instead of -log10 P-value

[amkwong]

The P-value filter in a LocusZoom plot currently uses -log10 P-values as the input value to filter points. Since for researchers it's more intuitive to type in a P-value directly (e.g. '5e-8'), we want to support using actual P-values in that filter text box.

How to test:

Type in actual P-values in different formats and make sure the filter value is correct. Example of different formats: "0.05", ".001", "5e-8"