Remove table-layout: fixed style from the tree table of files

This causes invalid columns widths on mobile devices
because `table-layout: fixed` calculates widths just once
using the first available row which is the row with the
button 'Go up'.

Changelog: fixed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/69445

app/assets/stylesheets/pages/tree.scss

@@ -102,7 +102,6 @@
 
   .tree-table {
     margin-bottom: 0;
-    table-layout: fixed;
 
     tr {
       border-bottom: 1px solid $white-normal;