Revert "FIX: Require q param in /tags/filter/search route (#8263)"

This reverts commit 968a1419df.

spec/requests/tags_controller_spec.rb

@@ -428,15 +428,6 @@ describe TagsController do
         json = ::JSON.parse(response.body)
         expect(json["results"].map { |j| j["id"] }).to eq(['тема-в-разработке'])
       end
-
-      context 'when tag query parameter is not provided' do
-        it 'does not cause a 500 error, returns a param required message' do
-          get "/tags/filter/search.json", params: {}
-          expect(response.status).to eq(400)
-          json = ::JSON.parse(response.body)
-          expect(json['errors']).to include('param is missing or the value is empty: q')
-        end
-      end
     end
   end