Add link to vulnerability from created issue

ee/app/views/vulnerabilities/issue_description.md.erb

+<% if vulnerability.is_a? Vulnerability %>
+Issue created from vulnerability <%= link_to vulnerability.id, Gitlab::UrlBuilder.build(vulnerability) %>
+
+<% end %>
 ### <%= _("Description") %>:
 
 <%= vulnerability.description %>

ee/changelogs/unreleased/add_link_to_vulnerability_from_issue.yml

+---
+title: Add link to vulnerability from created issue
+merge_request: 43046
+author:
+type: changed

ee/spec/services/ee/issues/create_from_vulnerability_service_spec.rb

@@ -97,6 +97,8 @@ RSpec.describe Issues::CreateFromVulnerabilityService, '#execute' do
       let(:expected_title) { "Investigate vulnerability: #{vulnerability.title}" }
       let(:expected_description) do
         <<~DESC.chomp
+          Issue created from vulnerability <a href="http://localhost/#{group.name}/#{project.name}/-/security/vulnerabilities/#{vulnerability.id}">#{vulnerability.id}</a>
+
           ### Description:
 
           Description of #{vulnerability.title}