Adjust user API specs to expect users without assigned teams.

In  d5d804a56f, the user API was changed to
also return users without an assigned team, but specs were not adjusted.

spec/services/api/v1/users_collection_spec.rb

@@ -9,8 +9,8 @@ describe Api::V1::UsersCollection do
         3.times { create(:user) }
       end
 
-      it "returns 0 results" do
-        expect(collection.execute_query.size).to eq(0)
+      it "returns 3 results" do
+        expect(collection.execute_query.size).to eq(3)
       end
     end