Bug: S3 bucket static website hosting requires an index document value, even if it's just one space (when set in the management console)

The AWS S3 service allows turning on static website hosting on a S3 bucket.

In the AWS CloudFormation user guide, the IndexDocument field is specified as optional (Required: No).

However, in the management console, when configuring an S3 bucket for static website hosting, the "Error document" field is marked "optional", meanwhile "Index document" is not, and trying to save the changes with that field left blank doesn't work (it is highlighted with "Must be at least 1 characters long."). Making "Index document" one empty space makes it no problem.

This is in line with what the S3 user guide says:

When you enable website hosting, you must also configure and upload an index document.

Steps to reproduce

• View a specific S3 bucket in the S3 management console
• In the "Properties" tab, scroll down to "Static website hosting" and click "Edit"
• Under "Static website hosting", select "Enable"
• Leave "Index document" blank
• Click "Save changes"

The "Index document" field will be highlighted in red with "Must be at least 1 characters long."

• Enter one empty space in the "Index document" field
• Click "Save changes"

The changes will now be saved.

Expected results

"Index document" should be optional.