fix: throw error when trying to add collection, area, editor to a collection

[prabalsingh24]

Problem

If you select Editor or Area or Collection in the search results, you can press Add to collection button and it doesn't throw any error.

Solution

[prabalsingh24]

Test for this is added in the PR 477

[coveralls]

Coverage decreased (-0.03%) to 58.073% when pulling a37fef9 on prabalsingh24:fix-checkEntityTypeBeforeAdding into d1fd35b on bookbrainz:UserCollection.

[MonkeyDo]

Nice catch !
I hadn't thought about that at all.