Attachment controls should not allow the alert level and message to be overridden for size constraints

[avernet]

The Single File Attachment control supports a Maximum Attachment Size constraint, while the Multiple File Attachments control supports both Maximum Attachment Size per File and Maximum Aggregate Attachment Size constraints. When any of these constraints are not met, an error dialog is immediately displayed, and the file is rejected. Therefore, there is no concept of "level," and form authors cannot customize the error message.

Consequently, we should either hide or disable the Level and Alert Message options. I would recommend hiding them, as disabling might lead users to believe that the displayed value is in use but unchangeable. This is misleading because having a Level = Error is not equivalent to rejecting the file outright, and the message displayed to users is not "Missing or incorrect value."