Expand the instrumentation FF coverage

Adding more code under the feature flag which is related to the
Instrumentation intialization and would be removed alongside the code
which is already under the FF.

config/initializers/zz_metrics.rb

@@ -162,25 +162,25 @@ if Gitlab::Metrics.enabled? && !Rails.env.test? && !(Rails.env.development? && d
     config.middleware.use(Gitlab::Metrics::ElasticsearchRackMiddleware)
   end
 
-  # This instruments all methods residing in app/models that (appear to) use any
-  # of the ActiveRecord methods. This has to take place _after_ initializing as
-  # for some unknown reason calling eager_load! earlier breaks Devise.
-  Gitlab::Application.config.after_initialize do
-    # We should move all the logic of this file to somewhere else
-    # and require it after `Rails.application.initialize!` in `environment.rb` file.
-    models_path = Rails.root.join('app', 'models').to_s
-
-    Dir.glob("**/*.rb", base: models_path).sort.each do |file|
-      require_dependency file
-    end
+  # We are removing the Instrumentation module entirely in steps.
+  # More in https://gitlab.com/gitlab-org/gitlab/-/issues/217978.
+  unless ::Feature.enabled?(:method_instrumentation_disable_initialization)
+    # This instruments all methods residing in app/models that (appear to) use any
+    # of the ActiveRecord methods. This has to take place _after_ initializing as
+    # for some unknown reason calling eager_load! earlier breaks Devise.
+    Gitlab::Application.config.after_initialize do
+      # We should move all the logic of this file to somewhere else
+      # and require it after `Rails.application.initialize!` in `environment.rb` file.
+      models_path = Rails.root.join('app', 'models').to_s
+
+      Dir.glob("**/*.rb", base: models_path).sort.each do |file|
+        require_dependency file
+      end
 
-    regex = Regexp.union(
-      ActiveRecord::Querying.public_instance_methods(false).map(&:to_s)
-    )
+      regex = Regexp.union(
+        ActiveRecord::Querying.public_instance_methods(false).map(&:to_s)
+      )
 
-    # We are removing the Instrumentation module entirely in steps.
-    # More in https://gitlab.com/gitlab-org/gitlab/-/issues/217978.
-    unless ::Feature.enabled?(:method_instrumentation_disable_initialization)
       Gitlab::Metrics::Instrumentation
         .instrument_class_hierarchy(ActiveRecord::Base) do |klass, method|
           # Instrumenting the ApplicationSetting class can lead to an infinite
@@ -199,9 +199,7 @@ if Gitlab::Metrics.enabled? && !Rails.env.test? && !(Rails.env.development? && d
       # be instrumented.
       Gitlab::Metrics::Instrumentation.instrument_methods(Ability)
     end
-  end
 
-  unless ::Feature.enabled?(:method_instrumentation_disable_initialization)
     Gitlab::Metrics::Instrumentation.configure do |config|
       instrument_classes(config)
     end