IMAP BODYSTRUCTURE parse error with long, encoded filenames

[marcelmay]

Based on #483 (thanks to @boris-petrov and @Mulgish for reporting):

When using MimeUtility#encodeText for creating mail with encoded and long attachment filename, the created mail contains an illegal CRLF in the Content-Disposition header.

SMTP trace, CRLF after 'esti?=':

13:39:34,487 (smtp:127.0.0.1:3025<-/127.0.0.1:63907) DEBUG         util.LineLoggingBuffer| C: Content-Disposition: attachment; \r\n
13:39:34,487 (smtp:127.0.0.1:3025<-/127.0.0.1:63907) DEBUG         util.LineLoggingBuffer| C: \tfilename*0="=?UTF-8?Q?=D0=BA=D0=B8=D1=80=D0=B8=D0=BB=D0=B8=D1=86=D0=B0_t"; \r\n

# UNEXPECTED CRLF IN NEXT LINE
13:39:34,488 (smtp:127.0.0.1:3025<-/127.0.0.1:63907) DEBUG         util.LineLoggingBuffer| C: \tfilename*1="esti?=\r\n

13:39:34,488 (smtp:127.0.0.1:3025<-/127.0.0.1:63907) DEBUG         util.LineLoggingBuffer| C:  =?UTF-8?Q?mage=5F=C3=BCnic=C3=B6de=5F=F0=9F=8C=B6?="\r\n

This will fail an IMAP client trying to read and parse the mail:

13:39:34,642 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| C: A4 FETCH 1 (BODYSTRUCTURE)\r\n
13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S: * 1 FETCH (BODYSTRUCTURE (("TEXT" "PLAIN" ("charset" "us-ascii") NIL NIL "7bit" 4 1 NIL NIL NIL)("IMAGE" "GIF" ("name*0" "=?UTF-8[WRAP]
13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S: ?Q?=D0=BA=D0=B8=D1=80=D0=B8=D0=BB=D0=B8=D1=86=D0=B0_t" "name*1" "esti?= =?UTF-8?Q?mage=5F=C3=BCnic=C3=B6de=5F=F0=9F=8C=B6?=") NIL[WRAP]
13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S:  "testimage_description" "base64" 4 NIL ("attachment" ("filename*0" "=?UTF-8?Q?=D0=BA=D0=B8=D1=80=D0=B8=D0=BB=D0=B8=D1=86=D0=B0_t[WRAP]

# UNEXPECTED CRLF IN NEXT LINE
13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S: " "filename*1" "esti?=\r\n

13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S:  =?UTF-8?Q?mage=5F=C3=BCnic=C3=B6de=5F=F0=9F=8C=B6?=")) NIL) "mixed" ("boundary" "----=_Part_0_1540374340.1667651974397") NIL NIL[WRAP]
13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S: ))\r\n
13:39:34,643 (imap:127.0.0.1:3143<-/127.0.0.1:63908) DEBUG         util.LineLoggingBuffer| S: A4 OK FETCH completed.\r\n

Failing client:

jakarta.mail.MessagingException: Unable to load BODYSTRUCTURE
	at com.sun.mail.imap.IMAPMessage.loadBODYSTRUCTURE(IMAPMessage.java:1540)
	at com.sun.mail.imap.IMAPMessage.getDataHandler(IMAPMessage.java:784)
	at jakarta.mail.internet.MimeMessage.getContent(MimeMessage.java:1484)

Seems related to line break for long filenames.