Change public accounts pages to mount the web UI (#19319)

* Change public accounts pages to mount the web UI

* Fix handling of remote usernames in routes

- When logged in, serve web app
- When logged out, redirect to permalink
- Fix `app-body` class not being set sometimes due to name conflict

* Fix missing `multiColumn` prop

* Fix failing test

* Use `discoverable` attribute to control indexing directives

* Fix `<ColumnLoading />` not using `multiColumn`

* Add `noindex` to accounts in REST API

* Change noindex directive to not be rendered by default before a route is mounted

* Add loading indicator for detailed status in web UI

* Fix missing indicator appearing while account is loading in web UI

spec/requests/account_show_page_spec.rb

@@ -3,17 +3,6 @@
 require 'rails_helper'
 
 describe 'The account show page' do
-  it 'Has an h-feed with correct number of h-entry objects in it' do
-    alice = Fabricate(:account, username: 'alice', display_name: 'Alice')
-    _status = Fabricate(:status, account: alice, text: 'Hello World')
-    _status2 = Fabricate(:status, account: alice, text: 'Hello World Again')
-    _status3 = Fabricate(:status, account: alice, text: 'Are You Still There World?')
-
-    get '/@alice'
-
-    expect(h_feed_entries.size).to eq(3)
-  end
-
   it 'has valid opengraph tags' do
     alice = Fabricate(:account, username: 'alice', display_name: 'Alice')
     _status = Fabricate(:status, account: alice, text: 'Hello World')
@@ -33,8 +22,4 @@ describe 'The account show page' do
   def head_section
     Nokogiri::Slop(response.body).html.head
   end
-
-  def h_feed_entries
-    Nokogiri::HTML(response.body).search('.h-feed .h-entry')
-  end
 end