Update the text-encode-and-split test to the new internal API
Update the text-encode-and-split test to the new internal API

I had added a 'max lenth' parameter to the function but apparently forgot to
update this test.

freedesktop-unofficial-mirror/telepathy__telepathy-idle,freedesktop-unofficial-mirror/telepathy__telepathy-idle,freedesktop-unofficial-mirror/telepathy__telepathy-idle