Fix dashboard warning about Elasticsearch index mismatch not showing up (#34567)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

spec/lib/admin/system_check/elasticsearch_check_spec.rb

@@ -29,6 +29,9 @@ RSpec.describe Admin::SystemCheck::ElasticsearchCheck do
             },
           },
         })
+        [AccountsIndex, StatusesIndex, PublicStatusesIndex, InstancesIndex, TagsIndex].each do |index|
+          allow(index).to receive(:specification).and_return(instance_double(Chewy::Index::Specification, changed?: false))
+        end
       end
 
       context 'when running version is present and high enough' do