All devices are not visible when device list is large.

Problem/Motivation

When i add large number devices in the list then all devices are not visible on the selection.

Steps to reproduce

1) Go to "/admin/config/user-interface/responsive-preview" and Add atleast 20 devices.
2) Visit any content page, Click on preview icon present in admin toolbar.
3) You will see not all devices are visible under dropdown.

Proposed resolution

Add scrollbar.

Remaining tasks

User interface changes

API changes

Data model changes