tfhe_rust: add end-to-end testing to Github CI

[j2kun]

We'd need to install the rust toolchain as part of the CI setup, but otherwise it should work.

For Google reasons I don't think we can add it by default to the entire bazel build, but we could use the following script to run the rust tests as a last step in the GitHub workflow.

bazel query "filter('.mlir.test$', //tests/tfhe_rust/end_to_end/...)" \
  | xargs bazel test --sandbox_writable_path=$HOME/.cargo "$@"