GUI: Save list errors with "ListWidget::drawFormattedText(): Malformatted \\001C color"

[sluicebox]

On the save list, saving over an existing slot and pressing backspace all the way to the start of the string errors with:

ListWidget::drawFormattedText(): Malformatted \001C color (

There are other visual indicators before the error that something is off.

To reproduce:

1. Save a game, launching the ScummVM save UI
2. Set the mode to list
3. Save a game in a new slot and name it "test". (Notice that when the slot is selected, the selection color is no longer drawn until typing begins. That's new behavior.)
4. Save a second game, launching the ScummVM save UI again
5. Select the "test" slot
6. Notice the cursor is blinking far to the right of the text
7. Press backspace until all text is removed, then press again for error

[sev-]

Fixed.