[tests] Ignore LinkSdkRegressionTest.AsQueryable_Enumerable due to an issue in .NET

Ref: https://github.com/dotnet/runtime/issues/41392

Fixes this link sdk test failure:

    LinkSdk.LinkSdkRegressionTest
        [FAIL] AsQueryable_Enumerable : System.NullReferenceException : Object reference not set to an instance of an object
            at System.Linq.EnumerableRewriter.FindEnumerableMethod(String name, ReadOnlyCollection`1 args, Type[] typeArgs)
            at System.Linq.EnumerableRewriter.VisitMethodCall(MethodCallExpression m)
            at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor visitor)
            at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
            at System.Linq.Expressions.ExpressionVisitor.Visit(ReadOnlyCollection`1 nodes)
            at System.Linq.EnumerableRewriter.VisitMethodCall(MethodCallExpression m)
            at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor visitor)
            at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
            at System.Linq.EnumerableExecutor`1[[System.Linq.IGrouping`2[[System.String, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.String, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Linq, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].Execute()
            at System.Linq.EnumerableQuery`1[[System.Linq.IGrouping`2[[System.String, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.String, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Linq, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a]].System.Linq.IQueryProvider.Execute[IGrouping`2](Expression expression)
            at System.Linq.Queryable.FirstOrDefault[IGrouping`2](IQueryable`1 source)
            at LinkSdk.LinkSdkRegressionTest.AsQueryable_Enumerable() in /Users/rolf/work/maccore/whatever/xamarin-macios/tests/linker/ios/link sdk/LinkSdkRegressionTest.cs:line 1100
            at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)

tests/linker/ios/link sdk/LinkSdkRegressionTest.cs

@@ -1092,6 +1092,9 @@ namespace LinkSdk {
 		}
 #endif
 
+#if NET
+		[Ignore ("https://github.com/mono/linker/issues/1453")]
+#endif
 		[Test]
 		// https://github.com/xamarin/xamarin-macios/issues/6346
 		public void AsQueryable_Enumerable ()