[LLDB] Use non synthetic value for MSVC smart ptr check (#148176)

I forgot to use the non-synthetic value to check for the `_Ptr` member.

Fixes the test failure from #147575.

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Co-authored-by: Michael Buch <michaelbuch12@gmail.com>

Author: Nerixyz

lldb/source/Plugins/Language/CPlusPlus/MsvcStlSmartPointer.cpp

@@ -15,7 +15,10 @@
 using namespace lldb;
 
 bool lldb_private::formatters::IsMsvcStlSmartPointer(ValueObject &valobj) {
-  return valobj.GetChildMemberWithName("_Ptr") != nullptr;
+  if (auto valobj_sp = valobj.GetNonSyntheticValue())
+    return valobj_sp->GetChildMemberWithName("_Ptr") != nullptr;
+
+  return false;
 }
 
 bool lldb_private::formatters::MsvcStlSmartPointerSummaryProvider(