Fix RS dashboard for auths without Web App

RS auths without a valid domain name will not fetch any metadata and
therefore not create a WebApp record. This fixes icons being looked up
anyway, resulting in exceptions

spec/components/app_catalog/web_app_icon_component_spec.rb

@@ -0,0 +1,11 @@
+require "rails_helper"
+
+RSpec.describe AppCatalog::WebAppIconComponent, type: :component do
+  describe "No web app given" do
+    it "renders the default icon" do
+      expect(
+        render_inline(described_class.new(web_app: nil)) {}.to_html
+      ).to include("icon-remotestorage")
+    end
+  end
+end