Wrong encoding, conversion from "unicode-1-1-utf-7"

[matidau]

Describe the bug
unicode-1-1-utf-7 not treated as utf-7

From https://discourse.mailinabox.email/t/problems-with-z-push-mail-sync-after-each-upgrade-of-miab/12145/6

Expected behavior
Convert to utf-8 from utf-7

Logs
26/07/2024 03:05:21 [183171] [WARN][@.] /usr/local/lib/z-push/lib/utils/utils.php:1284 iconv(): Wrong encoding, conversion from "unicode-1-1-utf-7" to "utf-8" is not allowed (2)