Convert modules below in build/make/target/product/gsi/Android.mk to Android.bp

- init.gsi.rc
- init.vndk-nodef.rc

Bug: 371111740
Change-Id: I34fa17f8239ec965168e1b3931af66b4efb90de0
Test: lunch aosp_arm64-trunk_staging-eng && m && ls out/target/product/generic_arm64/system/system_ext/etc/init/init.gsi.rc out/target/product/generic_arm64/system/system_ext/etc/gsi/init.vndk-nodef.rc