doc: add limitations (#2484)

Added a sentence indicating that shadow properties cannot be accessed if the entity returned as no-tracking

Author: shahabganji

entity-framework/core/modeling/shadow-properties.md

@@ -41,3 +41,5 @@ Shadow properties can be referenced in LINQ queries via the `EF.Property` static
 var blogs = context.Blogs
     .OrderBy(b => EF.Property<DateTime>(b, "LastUpdated"));
 ```
+
+Shadow properties cannot be accessed after a no-tracking query since the entities returned are not tracked by the change tracker.