Incorrect behavior of `archive` argument in `LegacyWrapper.scan_postbox`

[maresb]

With #72 applied, I observe strange behavior regarding the archive and download_all arguments. There are four cases. (In all four cases I set prepend_date=True. I haven't had a chance to debug this.

If I set archive=False and download_all=False I get:

old_document_dic = lw.scan_postbox(
    "old-postbox", download_all=False, archive=False, prepend_date=True
)

{'Mitteilungen': {'name': 'Mitteilungen',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=%24inbox',
  'documents': {}},
 'Vertragsinformationen': {'name': 'Vertragsinformationen',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=%24vertragsinformationen',
  'documents': {}},
 'Kontoauszüge': {'name': 'Kontoauszüge',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=%24kontoauszuege',
  'documents': {}},
 'Kreditkartenabrechnungen': {'name': 'Kreditkartenabrechnungen',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=%24kreditkartenabrechnungen',
  'documents': {}},
 'Wertpapierdokumente': {'name': 'Wertpapierdokumente',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=%24wertpapierdokumente',
  'documents': {}},
 'Steuerbescheinigungen': {'name': 'Steuerbescheinigungen',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=%24steuerbescheinigungen',
  'documents': {}},
 'Archiv': {'name': 'Archiv',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=archiv',
  'documents': {}},
 'Tresor': {'name': 'Tresor',
  'details': 'https://www.ib.dkb.de/ssohl/banking/postfach/ordner?$event=gotoFolder&folderNameOrId=tresor',
  'documents': {}}}

If I set archive=True and download_all=False I get the first page of 10 documents in my Archiv.

If I set archive=True and download_all=True I get the first page of 10 documents in my Archiv, but without downloading.

Setting archive=False and download_all=True it downloads all documents including from my Archiv.