This fixes stack overflow exceptions that would arise when a
`Current.Value` of 1 billion or more was set on a `SettingsNumberBox`.
The stack overflow was caused by the "maximum 9 digits" spec. If a value
technically within `int` bounds, but larger than 1 billion (in the range
[1,000,000,000; 2,147,483,647], to be more precise), a feedback loop
between the setting control's `Current` and its inner text box's
`Current` would occur, wherein the last digit would be trimmed and then
re-appended again forevermore.
To resolve, remove the offending spec and rely on `int.TryParse`
entirely to be able to discern overflow range. Additionally, UX of the
text box is slightly changed to notify when the `int` range is exceeded
with a red flash.
This behaviour would not have been possible to implement without recent
framework-side fixes to text box (removal of text set scheduling).
