chore: InternalVisibleTo Unity SDK tests (#4130)

Author: bitsandfoxes

src/Sentry/Sentry.csproj

@@ -22,6 +22,7 @@
 
   <ItemGroup Condition="'$(SolutionName)' == 'Sentry.Unity'">
     <InternalsVisibleTo Include="Sentry.Unity" />
+    <InternalsVisibleTo Include="Sentry.Unity.Tests" />
   </ItemGroup>
 
   <!-- Platform-specific props included here -->

src/Sentry/SentrySdk.cs

@@ -209,13 +209,6 @@ internal static IDisposable UseHub(IHub hub)
         return new DisposeHandle(hub);
     }
 
-    /// <summary>
-    /// Allows to set the trace
-    /// </summary>
-    internal static void SetTrace(SentryId traceId, SpanId parentSpanId) =>
-        CurrentHub.ConfigureScope(scope =>
-            scope.SetPropagationContext(new SentryPropagationContext(traceId, parentSpanId)));
-
     /// <summary>
     /// Flushes the queue of captured events until the timeout set in <see cref="SentryOptions.FlushTimeout"/>
     /// is reached.