Improve support for old browsers (#9515)

* FEATURE: Improve crawler view

* FIX: Make lazyYT crawler-friendly

* DEV: Rename discourse-internet-explorer to discourse-unsupported-browser

* DEV: Detect more unsupported browsers

Follow-up to 4eebbd221239eaa3fc7e6f1bd6a9dcf0239b8444.

* FIX: Hide browser update notice in print view

plugins/discourse-unsupported-browser/spec/middleware/anonymous_cache_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+describe Middleware::AnonymousCache::Helper do
+  def env(opts = {})
+    {
+      "HTTP_HOST" => "http://test.com",
+      "REQUEST_URI" => "/path?bla=1",
+      "REQUEST_METHOD" => "GET",
+      "rack.input" => ""
+    }.merge(opts)
+  end
+
+  def new_helper(opts = {})
+    Middleware::AnonymousCache::Helper.new(env(opts))
+  end
+
+  it "includes ie in cache key" do
+    helper = new_helper
+    expect(helper.cache_key).to include("ie=false")
+
+    helper = new_helper("HTTP_USER_AGENT" => "Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko")
+    expect(helper.cache_key).to include("ie=true")
+  end
+end