Fixes long commit messages overflow viewport in file tree

CHANGELOG

@@ -13,6 +13,7 @@ v 8.13.0 (unreleased)
   - Use a ConnectionPool for Rails.cache on Sidekiq servers
   - Only update issuable labels if they have been changed
   - Revoke button in Applications Settings underlines on hover.
+  - Fix Long commit messages overflow viewport in file tree
   - Update ruby-prof to 0.16.2. !6026 (Elan Ruusamäe)
   - Add organization field to user profile
   - Fix resolved discussion display in side-by-side diff view !6575

app/assets/stylesheets/pages/tree.scss

@@ -27,7 +27,12 @@
       }
 
       .last-commit {
-        @include str-truncated(60%);
+        @include str-truncated(506px);
+        
+        @media (min-width: $screen-sm-max) and (max-width: $screen-md-max) {
+          @include str-truncated(450px);
+        }
+        
       }
 
       .commit-history-link-spacer {