facets: handle non-existent vocabulary type

[ppanero]

• requires https://github.com/inveniosoftware/invenio-records-resources/pull/435
• closes https://github.com/inveniosoftware/invenio-app-rdm/issues/1952

In invenio-vocabularies we have read, read_all and read_many. When searching for generic vocabularies, we give two parameters vocabulary type and ids (e.g. resourcetype and publication). In the case that publication does not exist the result would be:

• read --> NoResultFound (404)
• read_many and read_all --> empty search result (i.e. hits: [])

However, all three methods assume that the vocabulary type (e.g. resourcetype) exists in db (we are querying .one() with no try/except). Then, it make the search page with a 404 because a NoResultFound is risen. It leads me to:

• read --> NoResultFound (404) . This is still correct, however, should we expose in the error if what does exist is the type instead of the actual id?
• read_many and read_all --> Here is the important part:
  • Imitating the empty search result (i.e. hits: []) would be the desired output for internal usage (e.g. facets). However, it is semantically incorrect, since it's not empty but rather doesn't exist.
  • 404, would need to handle this internally when labelling vocabularies <-- I'm leaning towards this solution, but would mean silent failure

[ppanero]

How it looks:

[ppanero]

test fail due to missing requirement https://github.com/inveniosoftware/invenio-records-resources/pull/435