Rename OccurrenceDiffSerializer to Finding

Rename Vulnerabilities::OccurrenceDiffSerializer to
Vulnerabilities::FindingDiffSerializer
Rename files and usages

ee/app/serializers/vulnerabilities/occurrence_diff_serializer.rb → ee/app/serializers/vulnerabilities/finding_diff_serializer.rb

 # frozen_string_literal: true
 
-class Vulnerabilities::OccurrenceDiffSerializer < BaseSerializer
+class Vulnerabilities::FindingDiffSerializer < BaseSerializer
   include WithPagination
 
   entity Vulnerabilities::OccurrenceReportsComparerEntity

ee/app/services/ci/compare_container_scanning_reports_service.rb

@@ -7,7 +7,7 @@ module Ci
     end
 
     def serializer_class
-      Vulnerabilities::OccurrenceDiffSerializer
+      Vulnerabilities::FindingDiffSerializer
     end
 
     def get_report(pipeline)

ee/app/services/ci/compare_dast_reports_service.rb

@@ -7,7 +7,7 @@ module Ci
     end
 
     def serializer_class
-      Vulnerabilities::OccurrenceDiffSerializer
+      Vulnerabilities::FindingDiffSerializer
     end
 
     def get_report(pipeline)

ee/app/services/ci/compare_dependency_scanning_reports_service.rb

@@ -7,7 +7,7 @@ module Ci
     end
 
     def serializer_class
-      Vulnerabilities::OccurrenceDiffSerializer
+      Vulnerabilities::FindingDiffSerializer
     end
 
     def get_report(pipeline)

ee/app/services/ci/compare_sast_reports_service.rb

@@ -7,7 +7,7 @@ module Ci
     end
 
     def serializer_class
-      Vulnerabilities::OccurrenceDiffSerializer
+      Vulnerabilities::FindingDiffSerializer
     end
 
     def get_report(pipeline)