[4.0] Web services content history endpoints need to be tested

[pjdevries]

The following endpoints were pluralized and must be tested:

v1/content/article/contenthistory/ became v1/content/articles/contenthistory/
v1/content/article/contenthistory/keep became v1/content/articles/contenthistory/keep

v1/contact/contenthistory/:id became v1/contacts/contenthistory/:id
v1/contact/contenthistory/keep/:id became v1/contacts/contenthistory/keep/:id

[alikon]

confirmed the GET on v1/content/articles/contenthistory/{{id}} and v1/contacts/contenthistory/{{id}}

return

{
    "links": {
        "self": "http://dev4.loc/api/index.php/v1/contacts/contenthistory/1"
    },
    "data": [],
    "meta": {
        "total-pages": 0
    }
}

even if there are history

[alikon]

@pjdevries please test #34447 fo the GET part