Change username full name back to only username on xs viewports

app/views/projects/builds/_user.html.haml

 by
 %a{ href: user_path(@build.user) }
-  = image_tag avatar_icon(@build.user, 24), class: "avatar s24"
-  %strong{ data: { toggle: 'tooltip', placement: 'top', title: @build.user.to_reference } }
-    = @build.user.name
+  %span.hidden-xs
+    = image_tag avatar_icon(@build.user, 24), class: "avatar s24"
+    %strong{ data: { toggle: 'tooltip', placement: 'top', title: @build.user.to_reference } }
+      = @build.user.name
+  %strong.visible-xs-inline= @build.user.to_reference