FMetadata: References to invalid\destructed objects can accumulate in the ObjectMetaDataMap array

Customers are reporting that the package metadata can end up referencing to non-existing assets or other assets. This causing validation errors in the editor and also generates warnings during the DDC commandlet. The customers could not provide a way to reproduce the problem but Claude was able to find the current reproduction steps. There might be more ways to generate bad references in the Metadata.

The current analysis is that it is caused by the ObjectMetaDataMap key using soft references. They are remapped by the core redirects when saving (FSoftObjectPath::PreSavePath).

• 1. Create BP_Test.
  2. Rename it to BP_Test2 (leaving a Core Redirect).
  3. Create a new BP_Test and save it.