Added the CI_REF_PROTECTED variable to the Gitlab runner

This variable shows if the branch the runner is executing is protected
or not.
References: #50909

app/models/ci/pipeline.rb

@@ -638,6 +638,7 @@ module Ci
         variables.append(key: 'CI_COMMIT_MESSAGE', value: git_commit_message.to_s)
         variables.append(key: 'CI_COMMIT_TITLE', value: git_commit_full_title.to_s)
         variables.append(key: 'CI_COMMIT_DESCRIPTION', value: git_commit_description.to_s)
+        variables.append(key: 'CI_REF_PROTECTED', value: protected_ref?.to_s)
 
         if merge_request_event? && merge_request
           variables.append(key: 'CI_MERGE_REQUEST_SOURCE_BRANCH_SHA', value: source_sha.to_s)

spec/models/ci/bridge_spec.rb

@@ -33,7 +33,7 @@ describe Ci::Bridge do
         CI_PROJECT_ID CI_PROJECT_NAME CI_PROJECT_PATH
         CI_PROJECT_PATH_SLUG CI_PROJECT_NAMESPACE CI_PIPELINE_IID
         CI_CONFIG_PATH CI_PIPELINE_SOURCE CI_COMMIT_MESSAGE
-        CI_COMMIT_TITLE CI_COMMIT_DESCRIPTION
+        CI_COMMIT_TITLE CI_COMMIT_DESCRIPTION CI_REF_PROTECTED
       ]
 
       expect(bridge.scoped_variables_hash.keys).to include(*variables)

spec/models/ci/build_spec.rb

@@ -2227,7 +2227,8 @@ describe Ci::Build do
           { key: 'CI_PIPELINE_SOURCE', value: pipeline.source, public: true, masked: false },
           { key: 'CI_COMMIT_MESSAGE', value: pipeline.git_commit_message, public: true, masked: false },
           { key: 'CI_COMMIT_TITLE', value: pipeline.git_commit_title, public: true, masked: false },
-          { key: 'CI_COMMIT_DESCRIPTION', value: pipeline.git_commit_description, public: true, masked: false }
+          { key: 'CI_COMMIT_DESCRIPTION', value: pipeline.git_commit_description, public: true, masked: false },
+          { key: 'CI_REF_PROTECTED', value: pipeline.protected_ref?.to_s, public: true, masked: false }
         ]
       end
 

spec/models/ci/pipeline_spec.rb

@@ -670,7 +670,8 @@ describe Ci::Pipeline, :mailer do
                             CI_PIPELINE_SOURCE
                             CI_COMMIT_MESSAGE
                             CI_COMMIT_TITLE
-                            CI_COMMIT_DESCRIPTION]
+                            CI_COMMIT_DESCRIPTION
+                            CI_REF_PROTECTED]
     end
 
     context 'when source is merge request' do