MLECO-3842, MLECO-3801, MLECO-3899: Minor improvements

Some minor improvements in this patch:

* Added notes on troubleshooting WSL2 build issues.
* Fixed a stray guard for MPS3_PLATFORM from noise reduction
  use-case.
* The default build script `build_default.py` will now return
  an error code to the calling process if it fails.

Change-Id: I4557a402646fdf903b2cb043bf68d5d0b0d12972
Signed-off-by: Kshitij Sisodia <kshitij.sisodia@arm.com>