Remove FF ci_set_project_default_git_depth

This commit removes the FF

app/models/project_ci_cd_setting.rb

@@ -37,8 +37,6 @@ class ProjectCiCdSetting < ApplicationRecord
   private
 
   def set_default_git_depth
-    return unless Feature.enabled?(:ci_set_project_default_git_depth, default_enabled: true)
-
     self.default_git_depth ||= DEFAULT_GIT_DEPTH
   end
 end

spec/models/project_ci_cd_setting_spec.rb

@@ -54,17 +54,5 @@ describe ProjectCiCdSetting do
 
       expect(project.reload.ci_cd_settings.default_git_depth).to eq(0)
     end
-
-    context 'when feature flag :ci_set_project_default_git_depth is disabled' do
-      let(:project) { create(:project) }
-
-      before do
-        stub_feature_flags(ci_set_project_default_git_depth: { enabled: false } )
-      end
-
-      it 'does not set default value for new records' do
-        expect(project.ci_cd_settings.default_git_depth).to eq(nil)
-      end
-    end
   end
 end