[v10.0.x] Nested folders: Fix folder hierarchy in folder responses

[papagian]

Backport 9fcee9b from #74516

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What is this feature?

#66835 modified the folder DTO to include the folder parents (if nested folders are enabled) to be used by the frontend the show the full path to Folders in the breadcrumbs.
When I implemented it I had in mind that ancestors not visible to the user (due to permissions) would be included as is and the frontend would handle them.
In retrospect, I realise that this problematic therefore I have made this fix that redacts their UID and the title instead.
It also fixes another bug (wrong guardian used) and populates correctly the canEdit, canView etc properties for ancestors.

Why do we need this feature?

[Add a description of the problem the feature is trying to solve.]

Who is this feature for?

[Add information on what kind of user the feature is for.]

Which issue(s) does this PR fix?:

Fixes #

Special notes for your reviewer:

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.