Missing text in HIGHESTMODSEQ response

[duesee]

Status responses in IMAP MUST have a non-empty text (and preceeding space).

resp-text = ["[" resp-text-code "]" SP] text
text      = 1*TEXT-CHAR
TEXT-CHAR = <any CHAR except CR and LF>

It was observed that Gmail has neither the SP nor the text when using HIGHESTMODSEQ.

Observed in: Gmail (Sep. 27, 2023)
Reported: Yes
Status: [Open](https://issuetracker.google.com/issues/289877509)
Comment: The examples in RFC 7162 are wrong, see [errata](https://www.rfc-editor.org/errata/eid5055).
Proposed solution(s):
    Wait for Gmail to fix it (or comment on issue)
    Replace with a sentinel value and log warning (implemented in [imap-codec](https://github.com/duesee/imap-codec))
    Discard, but make sure not to reproduce the defect