First paragraph, last line:

"Nothing in this section shall prohibit an inmate from working when the inmate has been duly convicted of a crime."

So, they are not prohibited from working. You know, like you and me.

Note the part that is being deleted from the state constitution:

"That slavery and involuntary servitude, except as a punishment for crime, whereof the party shall have been duly convicted, are forever prohibited in this state."

Replaced with:

"Slavery and involuntary servitude are forever prohibited."

Lawyers will argue over it, but the plain text seems pretty clear to me: prisoners can work if they want to, but can't be forced to work.