Add default implementation

Author: normj

Libraries/src/Amazon.Lambda.Core/ILambdaContext.cs

@@ -85,14 +85,16 @@ public interface ILambdaContext
         /// </summary>
         TimeSpan RemainingTime { get; }
 
+#if NET8_0_OR_GREATER
         /// <summary>
         /// Gets the tenant id for the Lambda function.
         /// </summary>
-        string TenantId { get; }
+        string TenantId { get { return string.Empty; } }
 
         /// <summary>
         /// The trace id generated by Lambda for distributed tracing across AWS services.
         /// </summary>
-        string TraceId { get; }
+        string TraceId { get { return string.Empty; } }
+#endif
     }
 }