Update IAuthorizationPolicyProvider.cs

Author: HaoK

src/Security/Authorization/Core/src/IAuthorizationPolicyProvider.cs

@@ -27,6 +27,6 @@ public interface IAuthorizationPolicyProvider
         /// Gets the fallback authorization policy.
         /// </summary>
         /// <returns>The fallback authorization policy.</returns>
-        Task<AuthorizationPolicy> GetFallbackPolicyAsync() => Task.FromResult<AuthorizationPolicy>(null);
+        Task<AuthorizationPolicy> GetFallbackPolicyAsync();
     }
 }