[Analyzers][CPP]Turn on C26495 and fix code (#21163)

C26495: A member variable isn't initialized by a constructor or by an initializer.
Fixing occurrences with default member initialization.

src/modules/fancyzones/FancyZonesLib/FancyZonesData/CustomLayouts.cpp

@@ -102,7 +102,7 @@ namespace JsonUtils
     
     struct CustomLayoutJSON
     {
-        GUID layoutId;
+        GUID layoutId{};
         FancyZonesDataTypes::CustomLayoutData data;
 
         static std::optional<CustomLayoutJSON> FromJson(const json::JsonObject& json)