This fixes a bug where a discussion on a none changed line
would not get fully removed and therefore leave the comment row
empty. This was caused by the discussiob being added
to the right when it shouldnt of been

This also fixes a very rare edge case where discussions would get added
twice to diff lines causing a Vue rendering warning

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/53317

Pre-request to https://gitlab.com/gitlab-org/gitlab-ce/issues/48956

Added tests to file row truncated text computed prop

This adds toggle buttons to switch between file & tree list.
For file list, it renders the truncated paths with the ellipsis
at the start of the path.

When focusing the input, it hides the toggle buttons.
On blur, the buttons get shown again.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/51859

Fix MR discussion not loaded issue

Closes #51958

See merge request gitlab-org/gitlab-ce!21982

This file tree displays all the diff files in a tree like format
Each file is taken and converted into a tree with folders
Each folder can be toggled open & closed
Clicking a file will scroll to the diff file & highlight with a glow affect

Searching the tree list will search only files & return a list of the
files without any folders

Each file row contains an icon to show changed, new file or deleted
Each row will also contain the added & removed lines count

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14249

Display `formatter` as the sole content of `position` object.
This means `diff_file` data is not referenced, which is the
caseu of "IOError: not opened for reading".