gn2bp: fix response_file_contents parsing am: c20887d2db

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2276596

Change-Id: Ie22cee9ac89061cef4586f10b5877d3a8450d325
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>