Fix encoding error for commits endpoint

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/407848

**Problem**

We started displaying tags on commits page. However, tags with UTF-8
characters raise an exception, because we don't encode them correctly.

**Solution**

Use 'Git#ref_name' to convert tag name to UTF-8 format.

Changelog: fixed

app/presenters/commit_presenter.rb

@@ -26,7 +26,7 @@ def any_pipelines?
   end
 
   def tags_for_display
-    commit.referenced_by&.map { |tag| tag.delete_prefix(Gitlab::Git::TAG_REF_PREFIX) }
+    commit.referenced_by&.map { |tag_name| Gitlab::Git.ref_name(tag_name) }
   end
 
   def signature_html

spec/controllers/projects/commits_controller_spec.rb

@@ -3,8 +3,9 @@
 require 'spec_helper'
 
 RSpec.describe Projects::CommitsController, feature_category: :source_code_management do
-  let(:project) { create(:project, :repository) }
-  let(:user) { create(:user) }
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:repository) { project.repository }
+  let_it_be(:user) { create(:user) }
 
   before do
     project.add_maintainer(user)
@@ -105,7 +106,22 @@
         expect_next_instance_of(CommitCollection) do |collection|
           expect(collection).to receive(:load_tags)
         end
+
         get :show, params: { namespace_id: project.namespace, project_id: project, id: 'master/README.md' }
+
+        expect(response).to have_gitlab_http_status(:ok)
+      end
+
+      context 'when tag has a non-ASCII encoding' do
+        before do
+          repository.add_tag(user, 'tést', 'master')
+        end
+
+        it 'does not raise an exception' do
+          get :show, params: { namespace_id: project.namespace, project_id: project, id: 'master' }
+
+          expect(response).to have_gitlab_http_status(:ok)
+        end
       end
 
       context 'when the show_tags_on_commits_view flag is disabled' do