Fix Rails/SaveBang Rubocop offenses for banzai modules

Contributing https://gitlab.com/gitlab-org/gitlab/-/issues/220040

.rubocop_manual_todo.yml

@@ -270,8 +270,6 @@ Rails/SaveBang:
     - 'spec/initializers/fog_google_https_private_urls_spec.rb'
     - 'spec/lib/after_commit_queue_spec.rb'
     - 'spec/lib/backup/manager_spec.rb'
-    - 'spec/lib/banzai/reference_parser/external_issue_parser_spec.rb'
-    - 'spec/lib/banzai/reference_redactor_spec.rb'
     - 'spec/lib/gitlab/alerting/alert_spec.rb'
     - 'spec/lib/gitlab/analytics/cycle_analytics/records_fetcher_spec.rb'
     - 'spec/lib/gitlab/auth/ldap/user_spec.rb'

spec/lib/banzai/reference_parser/external_issue_parser_spec.rb

@@ -21,7 +21,7 @@ RSpec.describe Banzai::ReferenceParser::ExternalIssueParser do
 
       levels.each do |level|
         it "creates reference when the feature is #{level}" do
-          project.project_feature.update(issues_access_level: level)
+          project.project_feature.update!(issues_access_level: level)
 
           visible_nodes = subject.nodes_visible_to_user(user, [link])
 

spec/lib/banzai/reference_redactor_spec.rb

@@ -64,7 +64,7 @@ RSpec.describe Banzai::ReferenceRedactor do
       let(:redactor) { described_class.new(Banzai::RenderContext.new(project, user)) }
 
       before do
-        project.update(pending_delete: true)
+        project.update!(pending_delete: true)
       end
 
       it 'redacts an issue attached' do