Unable to scroll on countries facet modal

[ishasinha1]

Expected behavior

You should be able to scroll down the list of countries in the modal. The entire modal should be displayed on the screen.

Actual behavior

You are unable to scroll on the modal that pops up. You can only tab through the list. The entire modal does not fit on the screen.

Steps to replicate

1. Go to https://dss-staging.princeton.edu/catalog.
2. Click on the 'Countries' facet to the left.
3. Click 'more' at the bottom of the list to display modal.

Impact of this bug

This bug makes the website difficult to navigate. Users might think that they cannot sort data by countries appearing later in the list.

Implementation notes, if any