Clean up evidence controller specs and fix one

Currently we don't show issues in release evidence
regardless of permissions.

Even for public issues of public projects.

app/policies/releases/evidence_policy.rb

@@ -15,6 +15,7 @@ module Releases
     # - Project
     # - Milestones
     # - Issues
+    # TODO: remove issues from this check: https://gitlab.com/gitlab-org/gitlab/-/issues/259674
     condition(:allowed_to_read_evidence) do
       can?(:read_release) &&
         can?(:download_code) &&

spec/controllers/projects/releases/evidences_controller_spec.rb

@@ -113,18 +113,6 @@ RSpec.describe Projects::Releases::EvidencesController do
 
         it_behaves_like 'does not show the issue in evidence'
 
-        context 'when the issue is confidential' do
-          let(:issue) { create(:issue, :confidential, project: project) }
-
-          it_behaves_like 'does not show the issue in evidence'
-        end
-
-        context 'when the user is the author of the confidential issue' do
-          let(:issue) { create(:issue, :confidential, project: project, author: user) }
-
-          it_behaves_like 'does not show the issue in evidence'
-        end
-
         context 'when project is private' do
           let(:project) { create(:project, :repository, :private) }
 
@@ -143,32 +131,16 @@ RSpec.describe Projects::Releases::EvidencesController do
 
         it_behaves_like 'does not show the issue in evidence'
 
-        context 'when the issue is confidential' do
-          let(:issue) { create(:issue, :confidential, project: project) }
-
-          it_behaves_like 'does not show the issue in evidence'
-        end
-
-        context 'when the user is the author of the confidential issue' do
-          let(:issue) { create(:issue, :confidential, project: project, author: user) }
-
-          it_behaves_like 'does not show the issue in evidence'
-        end
-
         context 'when project is private' do
           let(:project) { create(:project, :repository, :private) }
 
-          it 'returns evidence ' do
-            subject
-
-            expect(json_response).to eq(evidence.summary)
-          end
+          it_behaves_like 'does not show the issue in evidence'
         end
 
         context 'when project restricts the visibility of issues to project members only' do
           let(:project) { create(:project, :repository, :issues_private) }
 
-          it_behaves_like 'evidence not found'
+          it_behaves_like 'does not show the issue in evidence'
         end
       end