Remove prebuilts for Rust 1.70.0 am: 2b5ca928d3 am: 349455b3e1 am: 3fcb8ab69d

Original change: https://android-review.googlesource.com/c/platform/prebuilts/rust/+/2812802

Change-Id: I9bddf9a47e05dc583b229d58bffe66657d40baa6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>