Put feature flag for reading from finding_evidence

Changelog: changed
EE: true

ee/app/models/vulnerabilities/finding.rb

@@ -291,7 +291,7 @@ def build_evidence_source(data)
     end
 
     def evidence
-      evidence_data = finding_evidence.present? ? finding_evidence.data : metadata.dig('evidence')
+      evidence_data = finding_evidence.present? && Feature.enabled?(:vulnerability_finding_replace_metadata) ? finding_evidence.data : metadata.dig('evidence')
 
       {
         summary: evidence_data&.dig('summary'),

ee/spec/models/vulnerabilities/finding_spec.rb

@@ -899,9 +899,31 @@
       context 'with finding_evidence' do
         let(:finding_evidence) { build(:vulnerabilties_finding_evidence) }
         let(:finding) { finding_evidence.finding }
-        let(:evidence) { finding_evidence.data }
 
-        include_examples 'evidence schema'
+        before do
+          finding_evidence.data[:summary] = "finding_evidence Summary"
+          finding_evidence.save!
+        end
+
+        context 'when the vulnerability_finding_replace_metadata feature flag is off' do
+          let(:evidence) { finding.metadata['evidence'] }
+
+          before do
+            stub_feature_flags(vulnerability_finding_replace_metadata: false)
+          end
+
+          include_examples 'evidence schema'
+        end
+
+        context 'when the vulnerability_finding_replace_metadata feature flag is on' do
+          let(:evidence) { finding_evidence.data }
+
+          before do
+            stub_feature_flags(vulnerability_finding_replace_metadata: true)
+          end
+
+          include_examples 'evidence schema'
+        end
       end
     end