Don’t show close icon on flash warning

app/views/layouts/_flash.html.haml

@@ -8,5 +8,6 @@
       %div{ class: "flash-#{key} mb-2" }
         = sprite_icon(icons[key], size: 16, css_class: 'align-middle mr-1') unless icons[key].nil?
         %span= value
-        %div{ class: "close-icon-wrapper js-close-icon" }
-          = sprite_icon('close', size: 16, css_class: 'close-icon')
+        - if %w(alert notice success).include?(key)
+          %div{ class: "close-icon-wrapper js-close-icon" }
+            = sprite_icon('close', size: 16, css_class: 'close-icon')

changelogs/unreleased/remove-close-button-from-flash-warning.yml

+---
+title: Don’t show close icon on flash warning
+merge_request: 36581
+author:
+type: fixed

spec/views/layouts/_flash.html.haml_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'layouts/_flash' do
+  before do
+    allow(view).to receive(:flash).and_return(flash)
+    render
+  end
+
+  describe 'closable flash messages' do
+    %w(alert notice success).each do |flash_type|
+      let(:flash) { { flash_type => 'This is a closable flash message' } }
+
+      it 'shows a close button' do
+        expect(rendered).to include('js-close-icon')
+      end
+    end
+  end
+
+  describe 'non closable flash messages' do
+    %w(error message toast warning).each do |flash_type|
+      let(:flash) { { flash_type => 'This is a non closable flash message' } }
+
+      it 'shows a close button' do
+        expect(rendered).not_to include('js-close-icon')
+      end
+    end
+  end
+end