Merge Actor - Textures created with the "Merge" option are not visible in the Content Browser

A recent modification to the CB behavior made it so that only the main asset of a package is visible in the CB.

It was unknown, but the merge actor tool "Merge" option has been creating a single package for all its generated assets since forever. The other merge options (simplify, approximate...) are fine. All the assets from that single package are flagged as RF_Public.

We should change the Merge code to create a single package per asset.

• Place a few cubes in the scene
• Select all these cubes
• In the menu, under Actor -> Merge Actors -> Merge Actors Settings...
• Use the following settings: 
  • LOD Selection Type: Always use the lowest-detail LOD
  • Enable "Merge Materials"
• Click Merge Actors

Result: Only a static mesh is visible in the content browser

Expected Result: A static mesh, a material instance and texture(s) assets are visible