Add response.content_type checks for JSON to api/v1 request specs (#31981)

spec/requests/api/v1/statuses/histories_spec.rb

@@ -18,6 +18,8 @@ RSpec.describe 'API V1 Statuses Histories' do
 
       it 'returns http success' do
         expect(response).to have_http_status(200)
+        expect(response.content_type)
+          .to start_with('application/json')
         expect(response.parsed_body.size).to_not be 0
       end
     end