Update DAST On-Demand API Scan template

https://gitlab.com/gitlab-org/gitlab/-/merge_requests/76491

* replaces the DastSiteProfile ci variable from `DAST_API_SPECIFICATION` 
  to `DAST_API_OPENAPI` as suggested here
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/73564#note_738732568
* remove the `GIT_STRATEGY: none` as suggested here
  https://gitlab.com/gitlab-org/gitlab/-/issues/347255#note_754003722

ee/app/models/dast_site_profile.rb

@@ -42,7 +42,7 @@ class DastSiteProfile < ApplicationRecord
       if target_type == 'website'
         variables.append(key: 'DAST_WEBSITE', value: url)
       else
-        variables.append(key: 'DAST_API_SPECIFICATION', value: url)
+        variables.append(key: 'DAST_API_OPENAPI', value: url)
         variables.append(key: 'DAST_API_HOST_OVERRIDE', value: URI(url).host)
       end
 

ee/spec/models/dast_site_profile_spec.rb

@@ -239,7 +239,7 @@ RSpec.describe DastSiteProfile, type: :model do
         it 'returns a collection of variables with api configuration only', :aggregate_failures do
           expect(keys).not_to include('DAST_WEBSITE')
 
-          expect(collection).to include(key: 'DAST_API_SPECIFICATION', value: subject.dast_site.url, public: true)
+          expect(collection).to include(key: 'DAST_API_OPENAPI', value: subject.dast_site.url, public: true)
           expect(collection).to include(key: 'DAST_API_HOST_OVERRIDE', value: URI(subject.dast_site.url).host, public: true)
         end
       end

lib/gitlab/ci/templates/Security/DAST-On-Demand-API-Scan.gitlab-ci.yml

@@ -12,8 +12,6 @@ variables:
 dast:
   stage: dast
   image: $DAST_API_IMAGE
-  variables:
-    GIT_STRATEGY: none
   allow_failure: true
   script:
     - /peach/analyzer-dast-api