Remove Xamarin app examples

[EthanChangAED]

Type of issue

• Bug
• Enhancement
• Compliance
• Question
• Help wanted

Current Behavior

There are Xamarin app examples in the sample repository. However, those samples are out of date and problematic.

Expected Behavior

Remove the Samarin app related samples.

Steps To Reproduce

No response

Environment

- OS:
- Environment:
- Runtime:
- Nuget Version:
- Component:
- Server:
- Client:

Anything else?

No response