Remove FF ci_bridge_dependency_variables

It is already enabled by default.

app/models/ci/bridge.rb

@@ -7,7 +7,6 @@ module Ci
     include Importable
     include AfterCommitQueue
     include Ci::HasRef
-    extend ::Gitlab::Utils::Override
 
     InvalidBridgeTypeError = Class.new(StandardError)
     InvalidTransitionError = Class.new(StandardError)
@@ -200,13 +199,6 @@ module Ci
       end
     end
 
-    override :dependency_variables
-    def dependency_variables
-      return [] unless ::Feature.enabled?(:ci_bridge_dependency_variables, project, default_enabled: true)
-
-      super
-    end
-
     def target_revision_ref
       downstream_pipeline_params.dig(:target_revision, :ref)
     end

config/feature_flags/development/ci_bridge_dependency_variables.yml

----
-name: ci_bridge_dependency_variables
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/46530
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/273734
-type: development
-group: group::pipeline authoring
-default_enabled: true

spec/models/ci/bridge_spec.rb

@@ -356,14 +356,6 @@ RSpec.describe Ci::Bridge do
   describe '#dependency_variables' do
     subject { bridge.dependency_variables }
 
-    shared_context 'when ci_bridge_dependency_variables is disabled' do
-      before do
-        stub_feature_flags(ci_bridge_dependency_variables: false)
-      end
-
-      it { is_expected.to be_empty }
-    end
-
     context 'when downloading from previous stages' do
       let!(:prepare1) { create(:ci_build, name: 'prepare1', pipeline: pipeline, stage_idx: 0) }
       let!(:bridge) { create(:ci_bridge, pipeline: pipeline, stage_idx: 1) }
@@ -374,8 +366,6 @@ RSpec.describe Ci::Bridge do
       it 'inherits only dependent variables' do
         expect(subject.to_hash).to eq(job_variable_1.key => job_variable_1.value)
       end
-
-      it_behaves_like 'when ci_bridge_dependency_variables is disabled'
     end
 
     context 'when using needs' do
@@ -397,8 +387,6 @@ RSpec.describe Ci::Bridge do
       it 'inherits only needs with artifacts variables' do
         expect(subject.to_hash).to eq(job_variable_1.key => job_variable_1.value)
       end
-
-      it_behaves_like 'when ci_bridge_dependency_variables is disabled'
     end
   end
 end