Specs for validation error in API responses (#36507)

spec/requests/api/v1/accounts/credentials_spec.rb

@@ -91,6 +91,11 @@ RSpec.describe 'credentials API' do
         expect(response).to have_http_status(422)
         expect(response.content_type)
           .to start_with('application/json')
+        expect(response.parsed_body)
+          .to include(
+            error: /Validation failed/,
+            details: include(note: contain_exactly(include(error: 'ERR_TOO_LONG', description: /character limit/)))
+          )
       end
     end