Remove undefined confidence from code

ee/app/models/vulnerabilities/occurrence.rb

@@ -28,7 +28,7 @@ module Vulnerabilities
     attr_writer :sha
 
     CONFIDENCE_LEVELS = {
-      undefined: 0,
+      # undefined: 0, no longer applicable
       ignore: 1,
       unknown: 2,
       experimental: 3,

ee/lib/api/vulnerability_findings.rb

@@ -47,7 +47,7 @@ module API
         optional :confidence,
                  type: Array[String],
                  desc: 'Returns vulnerabilities belonging to specified confidence level: '\
-                       '`undefined`, `ignore`, `unknown`, `experimental`, `low`, `medium`, `high`, or `confirmed`. '\
+                       '`ignore`, `unknown`, `experimental`, `low`, `medium`, `high`, or `confirmed`. '\
                        'Defaults to all',
                  values: ::Vulnerabilities::Occurrence.confidences.keys,
                  default: ::Vulnerabilities::Occurrence.confidences.keys

ee/spec/models/vulnerability_spec.rb

@@ -7,7 +7,7 @@ describe Vulnerability do
   let(:severity_values) { { info: 1, unknown: 2, low: 4, medium: 5, high: 6, critical: 7 } }
 
   let(:confidence_values) do
-    { undefined: 0, ignore: 1, unknown: 2, experimental: 3, low: 4, medium: 5, high: 6, confirmed: 7 }
+    { ignore: 1, unknown: 2, experimental: 3, low: 4, medium: 5, high: 6, confirmed: 7 }
   end
   let(:report_types) do
     { sast: 0,