Remove stale sha256 pin from google_root_pem.

Website builds are failing: https://buildkite.com/gvisor/release/builds/5973

https://pki.goog/roots.pem is a living file that changes whenever Google
rotates its trusted root CAs, so a pinned sha256 inevitably goes stale and
breaks the website build with a checksum mismatch.

The block's own comment states the hash is "omitted here intentionally".
Actually omit it so cert-bundle rotations no longer break the build.

PiperOrigin-RevId: 927383776

Author: ayushr2

MODULE.bazel

@@ -115,7 +115,6 @@ http_file(
 # used in any part of the build other than as certificates present in images.
 http_file(
     name = "google_root_pem",
-    sha256 = "0d4b15a365e5158c1f9217b7827c5af8a9b86789e8cfbe21480a57c134fe9d01",
     urls = [
         "https://pki.goog/roots.pem",
     ],