Vanilla still uses deprecated load_on_low_memory property

The bug

From the 1.16.0 changelog:

Optimized sound loading - "load_on_low_memory" is now deprecated in sound_definitions.json, as all audio can now play on low memory devices

Despite this, vanilla still uses this useless option in tons and tons of vanilla sounds. There are too many to list here. Just open up sounds_definition.json in the 10+ vanilla slices to see.

Ideally, including invalid properties should raise a content log warning.