Rename ecomm_instrumentation feature flag

To follow-up the epic renaming, at:
https://gitlab.com/groups/gitlab-org/-/epics/6347

app/helpers/auth_helper.rb

@@ -170,7 +170,7 @@ module AuthHelper
   end
 
   def one_trust_enabled?
-    Feature.enabled?(:ecomm_instrumentation_google_analytics_cookies, nil, type: :ops) &&
+    Feature.enabled?(:ecomm_instrumentation, nil, type: :ops) &&
       extra_config.has_key?('one_trust_id') &&
       extra_config.one_trust_id.present? &&
       !current_user

config/feature_flags/ops/ecomm_instrumentation_google_analytics_cookies.yml → config/feature_flags/ops/ecomm_instrumentation.yml

 ---
-name: ecomm_instrumentation_google_analytics_cookies
+name: ecomm_instrumentation
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/71243
 rollout_issue_url:
 milestone: '14.4'

spec/helpers/auth_helper_spec.rb

@@ -324,9 +324,9 @@ RSpec.describe AuthHelper do
 
     subject(:one_trust_enabled?) { helper.one_trust_enabled? }
 
-    context 'with ecomm_instrumentation_google_analytics_cookies feature flag enabled' do
+    context 'with ecomm_instrumentation feature flag enabled' do
       before do
-        stub_feature_flags(ecomm_instrumentation_google_analytics_cookies: true)
+        stub_feature_flags(ecomm_instrumentation: true)
       end
 
       context 'when current user is set' do