Revert "Try updating image digests again" (#2786)

Reverts bazelbuild/continuous-integration#2781

Maybe causing more CI issues:
https://buildkite.com/bazel/google-bazel-presubmit/builds/107220#019ff7c8-b8c5-47d2-b418-2be090b8adf7

`OSError: [Errno 8] Exec format error: '/tmp/tmpsgtjeye3/bazelci-agent'`