[ui] Personal bookmarks used within collective dashboard doesn't work

For a collective dashboard, it seems possible to use personal bookmarks in search tiles, but this obviously doesn't work for any other users.

Either, personal bookmarks should not be on offer when designing a collective dashboard, or there ought to be a way to parametrise the bookmark, or — maybe the easiest — the bookmark should not be referenced by ID but by name, and each user just needs to create a personal bookmark.

The error message could also be improved:


Here is the use-case:

In the absence of workflows (#2272), I am forced to (ab)use tags and custom metadata to assign documents to users for approval. On the default dashboard of the collective, I want each user to have a list of items awaiting their approval.

Without a user enum (#2267), this has to thus be done using free-form text, which requires a different match expression for every user. Therefore, I created personal bookmarks for everyone, and I'd rather not have to maintain a personal dashboard for everyone too.