Cannot scroll 'Authorized Studies' modal's content on firefox

[evans-g-crsj]

A major refactor in the project (it touched the build process, css, ...) was made not too long ago.
Subtle and not so subtle regressions were introduced (especially with styling).

The following regression must be fixed : on firefox, go to the settings page -> connect to the 'Framework Services' and click on the 'view studies' button. A modal appears. There is no way to scroll when the content is long enough.

Add css to make content scrollable.