Fixes download button for artifacts rendering a huge block

app/assets/stylesheets/framework/layout.scss

@@ -115,9 +115,3 @@ body {
 .with-performance-bar .layout-page {
   margin-top: $header-height + $performance-bar-height;
 }
-
-.vertical-center {
-  min-height: 100vh;
-  display: flex;
-  align-items: center;
-}

app/views/projects/blob/viewers/_download.html.haml

 .file-content.blob_file.blob-no-preview
-  .center.render-error.vertical-center
+  .center.render-error
     = link_to blob_raw_path do
       %h1.light
         = sprite_icon('download')