Sort SAST_DEFAULT_ANALYZERS to support comparison

We need to sort SAST_DEFAULT_ANALYZERS so we can deterministically
compare it to the list of analyzers provided to the class.
The provided list of analyzers is also now being sorted.

ee/changelogs/unreleased/260331-sast-default-analyzers-bug.yml

+---
+title: Resolve "SAST_DEFAULT_ANALYZERS is written with default value by SAST Config UI"
+merge_request: 46388
+author:
+type: fixed

ee/lib/security/ci_configuration/sast_build_actions.rb

@@ -3,7 +3,7 @@
 module Security
   module CiConfiguration
     class SastBuildActions
-      SAST_DEFAULT_ANALYZERS = 'bandit, brakeman, gosec, spotbugs, flawfinder, phpcs-security-audit, security-code-scan, nodejs-scan, eslint, sobelow, pmd-apex, kubesec'
+      SAST_DEFAULT_ANALYZERS = 'bandit, brakeman, eslint, flawfinder, gosec, kubesec, nodejs-scan, phpcs-security-audit, pmd-apex, security-code-scan, sobelow, spotbugs'
 
       def initialize(auto_devops_enabled, params, existing_gitlab_ci_content)
         @auto_devops_enabled = auto_devops_enabled
@@ -55,6 +55,7 @@ module Security
                                                          config['analyzers']
                                                            &.select {|a| a['enabled'] }
                                                            &.collect {|a| a['name'] }
+                                                           &.sort
                                                            &.join(', ')
                                                        else
                                                          SAST_DEFAULT_ANALYZERS

ee/spec/lib/security/ci_configuration/sast_build_actions_spec.rb

@@ -64,11 +64,11 @@ RSpec.describe Security::CiConfiguration::SastBuildActions do
     params.merge( { 'analyzers' =>
                     [
                       {
-                        'name' =>  "brakeman",
+                        'name' =>  "flawfinder",
                         'enabled' =>  true
                       },
                       {
-                        'name' =>  "flawfinder",
+                        'name' =>  "brakeman",
                         'enabled' =>  true
                       }
                     ] }
@@ -305,6 +305,20 @@ RSpec.describe Security::CiConfiguration::SastBuildActions do
     end
   end
 
+  describe 'Security::CiConfiguration::SastBuildActions::SAST_DEFAULT_ANALYZERS' do
+    subject(:variable) {Security::CiConfiguration::SastBuildActions::SAST_DEFAULT_ANALYZERS}
+
+    it 'is sorted alphabetically' do
+      sorted_variable = Security::CiConfiguration::SastBuildActions::SAST_DEFAULT_ANALYZERS
+        .split(',')
+        .map(&:strip)
+        .sort
+        .join(', ')
+
+      expect(variable).to eq(sorted_variable)
+    end
+  end
+
   # stubbing this method allows this spec file to use fast_spec_helper
   def fast_auto_devops_stages
     auto_devops_template = YAML.safe_load( File.read('lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml') )