Correct CueSettingAlign.BadDelimiter test

Was asserting for error INVALID_CUESETTING_DELIMITER, however we've decided
that instead this should return WEBVTT_INVALID_CUESETTING as
"align;" is technically not a valid keyword. Also updated comments, 
linewrapping, and ensure that errorCount == 1 before trying to get the error.
 Requesting a pull to mozilla:dev from caitp:align-bad-delimiter