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/features/profile_spec.rb

@@ -18,36 +18,16 @@ feature 'Profile' do
     visit account_path('alice')
 
     is_expected.to have_title("alice (@alice@#{local_domain})")
-
-    within('.public-account-header h1') do
-      is_expected.to have_content("alice @alice@#{local_domain}")
-    end
-
-    bio_elem = first('.public-account-bio')
-    expect(bio_elem).to have_content(alice_bio)
-    # The bio has hashtags made clickable
-    expect(bio_elem).to have_link('cryptology')
-    expect(bio_elem).to have_link('science')
-    # Nicknames are make clickable
-    expect(bio_elem).to have_link('@alice')
-    expect(bio_elem).to have_link('@bob')
-    # Nicknames not on server are not clickable
-    expect(bio_elem).not_to have_link('@pepe')
   end
 
   scenario 'I can change my account' do
     visit settings_profile_path
+
     fill_in 'Display name', with: 'Bob'
     fill_in 'Bio', with: 'Bob is silent'
-    first('.btn[type=submit]').click
+
+    first('button[type=submit]').click
+
     is_expected.to have_content 'Changes successfully saved!'
-
-    # View my own public profile and see the changes
-    click_link "Bob @bob@#{local_domain}"
-
-    within('.public-account-header h1') do
-      is_expected.to have_content("Bob @bob@#{local_domain}")
-    end
-    expect(first('.public-account-bio')).to have_content('Bob is silent')
   end
 end