Send the entire loaded asset instead of decomposing it on the loader task.

[andriyDev]

Objective

• The previous state had the loader task send a single InternalAssetEvent::Loaded for every root asset and each of its subassets. The handle_internal_asset_events system reads these events one at a time. This means these two threads are racing. So it's possible to see some of the subassets loaded without the root asset being loaded in a frame, and then have to wait an additional frame to see the remaining subassets and root asset loaded.

Solution

• Instead of recursively sending the subassets inside the loader task, just send the LoadedAsset in its entirety.
• Do the recursion when processing the loaded asset. Since we're doing this in the system, the entire loaded asset will be processed in a single frame.
• This also reduces contention of the channel.

Testing

• None. This is kinda a "fake issue". In order to see it, handling a loaded asset in handle_internal_asset_events needs to finish the last received subasset before the loader task sends the root asset. This is probably pretty unlikely, but could in theory cause flaky tests.