IMAP Import - decoded filename as specified in RFC 2047, Section 6.1.

[rsoika]

If a imap mail contains an encoded filename we do not detect it as we do not decode it using the algorithm specified in RFC 2047, Section 6.1.
This leads to situations, where pdf attachments are not detached.

Example for a encoded filename:

Content-Disposition: attachment; filename=
	"=?iso-8859-1?Q?240108=5F352-01=5FTSP=5FRG#23120492_Lieferung_und_Montage_?=
 =?iso-8859-1?Q?Drucker_L=FCftungszentrale.pdf?="; size=587260;
	creation-date="Mon, 08 Jan 2024 08:38:48 GMT";
	modification-date="Mon, 08 Jan 2024 08:41:23 GMT"

This can easily be done by using

fileName = MimeUtility.decodeText(fileName);