[bug] canceling the editing of a prompt should reset the attachments and prompt

[csells]

this was broken when the attachments were fixed not to be removed when the user records a prompt

so the following should both work:

• editing an existing prompt and canceling that edit resetting the attachments and the prompt
• adding an attachment, recording a prompt and not clearing that attachment

[csells]

I believe this is fixed with v0.9.2.