Dashboard icon styling fix

When viewing a fresh install of GitLab on a mobile device, the styling for the dashboard item icon is broken in such a way that if the description div is more than 100px high, its contents wrap beneath the icon as shown below.

I modified the css for the icon and added a new class to the description div and now it behaves as expected as shown below.

As this is a purely html/css change, I don't believe it will break any tests. The only occurrence of .dashboard-intro-icon is in ./app/views/dashboard/_zero_authorized_projects.html.haml

Reassigned to @dzaporozhets

@dzaporozhets Looks good!

Thank you

mentioned in commit baf94a26

mentioned in commit 9843f9ee