AudioImporter - Preload Audio Data setting is showing up in per-platform settings but is changed for every platform.

How to reproduce:

1- Import an audio file in a new project (attached one to the bug report).
2- Select it to show its inspector.
3- On the per-platform settings, select standalone, check the override checkbox and change Preload Audio Data value.
4- Go back to the Default platform setting.

Expected result: Preload Audio Data is not changed in the default.
Actual result: Preload Audio Data was also changed in default and not only in the override.

Other information: The Load Type setting must not be Streaming or the bug will not show up because Preload Audio Data is enforced to false in that case.