Resolves#80117 by using the newer fetcher; see #79975 for details.
Would also be fixed by #80153 eventually, but we want to upgrade Rust packages
either way, so might as well start with the broken ones!
Changes the default fetcher in the Rust Platform to be the newer
`fetchCargoTarball`, and changes every application using the current default to
instead opt out.
This commit does not change any hashes or cause any rebuilds. Once integrated,
we will start deleting the opt-outs and recomputing hashes.
See #79975 for details.
