Fixes #2247. Preparing for the NStack v1.0.7 which now handling properly non-BMP code points.

[BDisp]

Fixes #2247 - There is still needed to fix non-BMP for the WindowsDriver and CursesDriver. For this to work is needed to install the NStack v1.0.7 which can now be published.

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui - if you use Visual Studio, hit CTRL-K-D to automatically reformat your files before committing.
• My code follows the Terminal.Gui library design guidelines
• I ran dotnet test before commit
• I have made corresponding changes to the API documentation (using /// style comments)
• My changes generate no new warnings
• I have checked my code and corrected any poor grammar or misspellings
• I conducted basic QA to assure all features are working

[tig]

@BDisp this PR fails to build.

[BDisp]

@BDisp this PR fails to build.

Because I couldn't update to the NStack v1.0.7 yet. You must republish it first.