Move members from ITraceContextInternal to interface ITraceContext

[jamescrosswell]

sentry-dotnet/src/Sentry/ITraceContextInternal.cs

Lines 3 to 19 in 3e70c31

	/// <summary>
	/// Internal interface defining members to be added to the TraceContexts for the next major release
	/// (since adding members to interfaces is a breaking change).
	/// </summary>
	/// <remarks>
	/// TODO: Remove this interface in the next major version.
	/// </remarks>
	internal interface ITraceContextInternal
	{
	/// <summary>
	/// Specifies the origin of the trace. If no origin is set then the trace origin is assumed to be "manual".
	/// </summary>
	/// <remarks>
	/// See https://develop.sentry.dev/sdk/performance/trace-origin/ for more information.
	/// </remarks>
	string? Origin { get; }
	}