Remove vendor_available from cargo2android.json. am: 43a62263d0 am: ae9ec6a74f

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/libloading/+/2834510

Change-Id: Iafee3e00d13d43149a2e0b68ea1f1974f97ccd7f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>