fix: Referer URL validation (#4309)

Fixes #354

spec/helpers/url_helper_spec.rb

@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+describe UrlHelper, type: :helper do
+  describe '#url_valid' do
+    context 'when url valid called' do
+      it 'return if valid url passed' do
+        expect(helper.url_valid?('https://app.chatwoot.com/')).to eq true
+      end
+
+      it 'return false if invalid url passed' do
+        expect(helper.url_valid?('javascript:alert(document.cookie)')).to eq false
+      end
+    end
+  end
+end