Apply minor tweaks for the Explain Vulnerability API

ee/app/models/ee/vulnerability.rb

@@ -230,7 +230,8 @@ def latest_state_transition
 
       def send_to_ai?
         ::Feature.enabled?(:explain_vulnerability, project) &&
-          finding&.ai_explainable?
+          finding.present? &&
+          !secret_detection?
       end
 
       private

ee/app/models/vulnerabilities/finding.rb

@@ -410,10 +410,6 @@ def last_finding_pipeline
       finding_pipelines.last&.pipeline
     end
 
-    def ai_explainable?
-      file.present? && location["start_line"].present?
-    end
-
     protected
 
     def primary_identifier_fingerprint

ee/lib/gitlab/llm/open_ai/templates/explain_vulnerability.rb

@@ -13,7 +13,7 @@ def initialize(vulnerability)
 
           def options
             {
-              max_tokens: ::Llm::ExplainCodeService::MAX_RESPONSE_TOKENS
+              max_tokens: 3_000
             }
           end
 

ee/spec/models/ee/vulnerability_spec.rb

@@ -954,6 +954,12 @@
         it { expect(vulnerability).to be_send_to_ai }
       end
 
+      context 'when the vulnerability is for a Secret Detection' do
+        let_it_be(:vulnerability) { create(:vulnerability, :secret_detection, :with_finding) }
+
+        it { expect(vulnerability).not_to be_send_to_ai }
+      end
+
       context 'when the vulnerability does not include a file' do
         let_it_be(:vulnerability) { create(:vulnerability, :with_finding) }
 
@@ -961,7 +967,7 @@
           vulnerability.finding.location.delete('file')
         end
 
-        it { expect(vulnerability).not_to be_send_to_ai }
+        it { expect(vulnerability).to be_send_to_ai }
       end
 
       context 'when the vulnerability does not include a start line' do
@@ -971,7 +977,7 @@
           vulnerability.finding.location.delete('start_line')
         end
 
-        it { expect(vulnerability).not_to be_send_to_ai }
+        it { expect(vulnerability).to be_send_to_ai }
       end
 
       context 'when the vulnerability does not include a finding' do