Allow nil on delegated CI/CD settings

This is a workaround for a race condition in which ci_cd_settings
is nil because the project is being deleted but not in a transaction
and so the project's delegates sometimes no longer exist while
the project still does

Changelog: fixed

app/models/project.rb

@@ -421,12 +421,12 @@ class Project < ApplicationRecord
   delegate :last_pipeline, to: :commit, allow_nil: true
   delegate :external_dashboard_url, to: :metrics_setting, allow_nil: true, prefix: true
   delegate :dashboard_timezone, to: :metrics_setting, allow_nil: true, prefix: true
-  delegate :default_git_depth, :default_git_depth=, to: :ci_cd_settings, prefix: :ci
-  delegate :forward_deployment_enabled, :forward_deployment_enabled=, :forward_deployment_enabled?, to: :ci_cd_settings, prefix: :ci
+  delegate :default_git_depth, :default_git_depth=, to: :ci_cd_settings, prefix: :ci, allow_nil: true
+  delegate :forward_deployment_enabled, :forward_deployment_enabled=, :forward_deployment_enabled?, to: :ci_cd_settings, prefix: :ci, allow_nil: true
   delegate :job_token_scope_enabled, :job_token_scope_enabled=, :job_token_scope_enabled?, to: :ci_cd_settings, prefix: :ci
-  delegate :keep_latest_artifact, :keep_latest_artifact=, :keep_latest_artifact?, :keep_latest_artifacts_available?, to: :ci_cd_settings
+  delegate :keep_latest_artifact, :keep_latest_artifact=, :keep_latest_artifact?, :keep_latest_artifacts_available?, to: :ci_cd_settings, allow_nil: true
   delegate :restrict_user_defined_variables, :restrict_user_defined_variables=, :restrict_user_defined_variables?,
-    to: :ci_cd_settings
+    to: :ci_cd_settings, allow_nil: true
   delegate :actual_limits, :actual_plan_name, to: :namespace, allow_nil: true
   delegate :allow_merge_on_skipped_pipeline, :allow_merge_on_skipped_pipeline?,
     :allow_merge_on_skipped_pipeline=, :has_confluence?, :allow_editing_commit_messages?,