Fix modification type icon in Web IDE file tree

Summary

Apparently introduced by !22364 (merged), there are now two modification type icons in the Web IDE file tree.

Steps to reproduce

1. Edit two files in the Web IDE: one in the root folder, and another in a subfolder

What is the current bug behavior?

1. There are duplicate icons for the root file
2. The subfolder file has only one icon and no options dropdown on hover

What is the expected correct behavior?

1. There's only one modification icon (the filled version, located on the right)
   1. The tooltip saying “Unstaged modification” should appear on hover
2. The options dropdown appears when hovering any file or folder, even in subfolders

Output of checks

This bug happens on GitLab.com