Fix column shifting in repository files with "..."

In this MR, we addressed the CLS (Cummulative Layout Shift) for the Repo file list without nested folders (without the "..." as the first row). However, that means the Repo file list with "..." will experience CLS:

cls-on-files-with-dir

Note, we can not simply just add table-layout: fixed because > !69445 (merged)

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 ....