Clean up App.xaml.cs

[MGGSK]

Cleaned up the app.xaml.cs file.

Description

1.Removed UWP code from the file. 2.Added comments to the file. 3.Made the code cleaner. 4.Removed unused code.

Motivation and Context

UWP code should not be in a WinUI app.

How Has This Been Tested?

No testing needed.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

[karkarl]

/azp run

[marcelwgn]

/azp run