junos_commit_check: retire sickbay after batfish/batfish#9934 fix

[dhalperi]

Remove IPv6 prefix normalization sickbay entries now that Batfish
issues fatal red flags for unnormalized IPv6 prefixes.

---

Prompt:

Fix https://github.com/batfish/batfish/issues/9934 . Note that we just
fixed the similar issue for IPv4. Apply the fix in ./batfish and then
test it by running batfish again (./batfish/tools/bazel_run.sh) and
testing lab-validation junos-commit-checks lab in ./lab-validation

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.50%. Comparing base (f17df9e) to head (20d919e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #174   +/-   ##
=======================================
  Coverage   83.50%   83.50%           
=======================================
  Files          87       87           
  Lines        4165     4165           
=======================================
  Hits         3478     3478           
  Misses        687      687           

Flag	Coverage Δ
unittests	83.50% <ø> (ø)

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