Return connection error for activation

Use different key to be distinguishable

ee/lib/gitlab/subscription_portal/clients/graphql.rb

@@ -6,6 +6,8 @@ module Gitlab
       module Graphql
         extend ActiveSupport::Concern
 
+        CONNECTIVITY_ERROR = 'CONNECTIVITY_ERROR'
+
         class_methods do
           def activate(activation_code)
             uuid = Gitlab::CurrentSettings.uuid
@@ -33,9 +35,7 @@ module Gitlab
               { query: query, variables: variables }
             )
 
-            if !response[:success] || response.dig(:data, 'errors').present?
-              return error(response.dig(:data, 'errors'))
-            end
+            return error(CONNECTIVITY_ERROR) unless response[:success]
 
             response = response.dig(:data, 'data', 'cloudActivationActivate')
 

ee/spec/lib/gitlab/subscription_portal/clients/graphql_spec.rb

@@ -49,6 +49,14 @@ RSpec.describe Gitlab::SubscriptionPortal::Clients::Graphql do
 
       expect(result).to eq({ errors: ["invalid activation code"], success: false })
     end
+
+    it 'returns connectivity error' do
+      stub_request(:any, EE::SUBSCRIPTIONS_GRAPHQL_URL).to_return(status: [500, "Internal Server Error"])
+
+      result = client.activate('activation_code_abc')
+
+      expect(result).to eq({ errors: described_class::CONNECTIVITY_ERROR, success: false })
+    end
   end
 
   describe '#plan_upgrade_offer' do