Remove ci_archived_build_trace_checksum feature flag

Changelog: added

config/feature_flags/development/ci_archived_build_trace_checksum.yml

----
-name: ci_archived_build_trace_checksum
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/70072
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/340737
-milestone: '14.4'
-type: development
-group: group::pipeline execution
-default_enabled: false

lib/gitlab/ci/trace/remote_checksum.rb

@@ -26,7 +26,6 @@ module Gitlab
         delegate :aws?, :google?, to: :object_store_config, prefix: :provider
 
         def fetch_md5_checksum
-          return unless Feature.enabled?(:ci_archived_build_trace_checksum, trace_artifact.project, default_enabled: :yaml)
           return unless object_store_config.enabled?
           return if trace_artifact.local_store?
 

spec/lib/gitlab/ci/trace/remote_checksum_spec.rb

@@ -30,14 +30,6 @@ RSpec.describe Gitlab::Ci::Trace::RemoteChecksum do
       context 'with remote files' do
         let(:file_store) { JobArtifactUploader::Store::REMOTE }
 
-        context 'when the feature flag is disabled' do
-          before do
-            stub_feature_flags(ci_archived_build_trace_checksum: false)
-          end
-
-          it { is_expected.to be_nil }
-        end
-
         context 'with AWS as provider' do
           it { is_expected.to eq(checksum) }
         end