Text Schema items are retained as a blank string in config when they're deleted from the setting

[maddox]

If a user edits a Text setting, but then goes back and removes it (deletes the string), the item stays in config as a blank zero length string.

This is a bit disruptive for dev because you have to check for existence AND if it's zero length, rather than just checking if it's set.

It would be nice if when a Text item is edited to zero length, it was removed from config.