Display device location code cleanup

[williambohrmann3]

Description

While triaging location display bugs, I noticed some areas of improvement for Display device location sample:

• Uses stack layouts instead of grids.
• Condenses start and stop button into one control with one click event handler.
• Shifts away from switch statement and implements dictionary.
• Updates UI when user pans map to indicate autopan mode change.
• Accurate readme.

The aim of this PR is to reduce the code verbosity while maintaining readability. Also, ensuring a consistently good UI/UX experience regardless of platform.

Type of change

• Sample code enhancement

Platforms tested on

• WPF .NET 6
• WPF Framework
• WinUI
• MAUI WinUI
• MAUI Android
• MAUI iOS
• MAUI MacCatalyst

Checklist

• Self-review of changes
• All changes work as expected on all affected platforms
• There are no warnings related to changes
• Code is commented and follows .NET conventions and standards
• Codemaid and XAML styler extensions have been run on every changed file
• No unrelated changes have been made to any other code or project files
• Screenshots are correct size and display in description tab (800 x 600 on Windows, MAUI mobile platforms use the MAUI Windows screenshot)