remove unnecessary util.Dedup and util.RightJoinMap methods

[imjasonh]

It's the future, we have generic slices and maps packages.

[imjasonh]

e2e failed with

2024/12/13 22:28:19 INFO running step "python/test"
2024/12/13 22:28:19 WARN Traceback (most recent call last):
2024/12/13 22:28:19 WARN   File "<string>", line 1, in <module>
2024/12/13 22:28:19 WARN ModuleNotFoundError: No module named 'numpy'
2024/12/13 22:28:19 INFO ERROR: failed to test package. the test environment has been preserved:
2024/12/13 22:28:19 INFO   workspace dir: /tmp/melange-workspace-2904734438
2024/12/13 22:28:19 INFO   guest dir: /tmp/melange-guest-608190734
2024/12/13 22:28:19 ERRO failed to test package: unable to run pipeline: unable to run pipeline: unable to run pipeline: exit status 1
ERROR[1]: Testing numpy-test from numpy-test.yaml

🤷

[jonjohnsonjr]

Rebase to pick up ba60467