SplitView Sample -> fix the mismatch between rendered content and source code

[Zakariathr22]

Description

A simple update to resolve discrepancies between the rendered content and the displayed source code, the only change is:

• Remove the code that does not match from the displayed source code (SplitViewPage.xaml).

Motivation and Context

• The similarity between SplitView and NavigationView might be confusing for learners, so it would be best to remove it.
• fixes this issue: SplitView Page - Mismatch between source code and rendered example #1587

How Has This Been Tested?

Manually Tested

Screenshots:

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

[karkarl]

/azp run

[karkarl]

@Zakariathr22 Thanks so much again for opening the series of PR's. Glad to have these merged in finally after an internal pipeline fiasco!

[Zakariathr22]

@karkarl Thanks so much for the time and effort on the review and for approving my ideas! 🙏 Excited to keep contributing! 🚀