Merge "Backport system default callback to Q" am: b616c88748 am: 9108c3c668 am: c7b75c82a0 am: 17f8551cef

Original change: https://android-review.googlesource.com/c/platform/packages/modules/NetworkStack/+/1760686

Change-Id: I080c07fdfa49e12c7ee006cb42362405f77284cb