CFMAIL doesn't default type to plain text when empty

this works on ACF, it defaults back to to text/plain
https://helpx.adobe.com/coldfusion/cfml-reference/coldfusion-tags/tags-m-o/cfmail.html

Lucee doesn't https://docs.lucee.org/reference/tags/mail.html#attribute-type

Lucee throws the following exception

https://github.com/lucee/Lucee/blob/5.3/core/src/main/java/lucee/runtime/tag/Mail.java#L279

The exception message should include the invalid value, the exception detail doesn't need the value(s)