certification bundle is created before user fs is setup properly

[blizzz]

1. Have user folders that are non-default, for instance per SAML or LDAP
2. Trigger the file system being setup (at least requiring an external storage from file_sharing being setup)
3. The DAV Storage initialization requests the certification bundle path in its constructor (https://github.com/nextcloud/server/blob/master/lib/private/Files/Storage/DAV.php#L118-L121). This happens within initMounPoints for the logged in user and write the file to the wrong location (the path as according to the mount, not the real one).

introduced with owncloud/core#25274