Fix missing GetEnableFabric implementation in QuirkSettings

Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com>

Author: Copilot

vnext/Microsoft.ReactNative/QuirkSettings.cpp

@@ -89,6 +89,11 @@ winrt::Microsoft::ReactNative::ReactPropertyId<bool> EnableSyncDetachRootViewPro
   return propId;
 }
 
+winrt::Microsoft::ReactNative::ReactPropertyId<bool> EnableFabricProperty() noexcept {
+  static winrt::Microsoft::ReactNative::ReactPropertyId<bool> propId{L"ReactNative.QuirkSettings", L"EnableFabric"};
+  return propId;
+}
+
 #pragma region IDL interface
 
 /*static*/ void QuirkSettings::SetMatchAndroidAndIOSStretchBehavior(
@@ -175,4 +180,8 @@ winrt::Microsoft::ReactNative::ReactPropertyId<bool> EnableSyncDetachRootViewPro
   return properties.Get(EnableSyncDetachRootViewProperty()).value_or(false);
 }
 
+/*static*/ bool QuirkSettings::GetEnableFabric(ReactPropertyBag properties) noexcept {
+  return properties.Get(EnableFabricProperty()).value_or(false);
+}
+
 } // namespace winrt::Microsoft::ReactNative::implementation