Migrate to cargo_embargo. am: 8b829742b4

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/form_urlencoded/+/2822399

Change-Id: I2be4a689874d689635fd696d9ad8129f9b8ff682
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>