In php class LegacyMapper\Configuration, in getMultiSiteSettings(), the value for site.ini/SiteSettings/DefaultPage is hardcoded to content/view/full/$rootNode

Esp. for admin siteaccess, it should be possible to change this to content/dashboard, without having to resort to write a custom event listener

Steps to reproduce:

1. Check that the DefaultPage setting in site.ini.append.php for the admin siteaccess (which uses legacy_mode):

   [SiteSettings]
   DefaultPage=content/dashboard
   

2. Login to admin, and verify that the default page is not content/dashboard