(fix): Resolved bug with Modal size for mobile viewport

Summary

Resolves UI bug for v2 modals when utilised within mobile browsers. If the height of the modal was bigger than the available viewport then the content was overflowing. Resolved by adding a min-height: -webkit-fill-available to the styling of the modal

Closes #5094 (closed)

Steps to test

Head to the Discovery section and open the Settings modal by clicking on the cog icon. Vertical viewport required must be equal to or smaller than the iPhone 7 viewport. Issue reported on iOS Safari.

Estimated Regression Scope

All v2 modals in Webkit browsers