Player is able to unintentionally install Add-Ons with missing dependencies when downloaded from the "Create New World" UI

Partner Rank: High

Verification Builds: 1.21.41 / 28695439 UWP

Regression Builds: Unknown

Summary: When downloading packs from the Marketplace using the "Create New World" UI, dependent behavior packs do not automatically attach, causing missing dependencies in newly created worlds.

Affects currently Live Content: Yes (all add-ons)

Impact: Players may unknowingly create worlds with incomplete content due to missing behavior pack dependencies, resulting in potential gameplay issues and error messages.

Repro Steps:

1. Click "Create New World."
2. Navigate to the "Resource Packs" tab.
3. In the "Owned" section, select and click "Activate" on a resource pack you own but have not yet downloaded.
4. Agree to download the pack.
5. Observe that the resource pack is activated and added, but the dependent behavior pack is not attached to the world.
6. Create the world and observe errors in the content log indicating missing dependencies.

Observed Results: The downloaded resource pack activates, but the associated behavior pack is not attached to the world, leading to missing dependencies and errors upon world creation.

Expected Results: When downloading and activating a resource pack, the behavior pack should also be attached to the world to ensure all dependencies are present when creating a world.

Workaround: Players must exit the "Create New World" screen and re-enter it to allow the resource and behavior packs to attach correctly. This workaround, however, may not be obvious to players.

Screenshots/Videos attached: Yes https://capture.dropbox.com/6NG3gZyAjHpvR0vu 

Notes:

• It seems to be problematic irrespective of the pack downloaded (i.e., it does not seem to be isolated to just Spark Pets).