[BUG] Application theme does not follow system choice

[mortenn]

Describe the bug
While the application thankfully does have a dark mode, it defaults to light mode even though my PC is set to use dark mode.
The application should follow the user preference rather than default to light mode; I assumed it only had light mode initially.

To Reproduce
Steps to reproduce the behavior:

1. Have windows set to use dark mode
2. Open IoT Explorer
3. Get blinded

Expected behavior
It should be in dark mode when launched

Desktop (please complete the following information):

• OS: Windows
• OS Version 11
• App version 0.15.8.0