Clean up py38 targets

[Abacn]

It is found settings.gradle.kts refers to some non-exist target. Also clean up TODOs post Python3.8 support removal

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[shunping]

r: @jrmccluskey

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[jrmccluskey]

LGTM

do the Jenkins targets actually matter? I've been meaning to go back and see how much of the old Jenkins code we can just delete

[Abacn]

LGTM

do the Jenkins targets actually matter? I've been meaning to go back and see how much of the old Jenkins code we can just delete

Yeah, as it already has a mismatch between gradle and tox file but not noticed, suggesting it's already dead code

EDIT: it is still used by https://github.com/apache/beam/actions/workflows/beam_Metrics_Report.yml, so leave it for now

[Naireen]

Looks like this broke some flink integration tests: https://github.com/apache/beam/actions/runs/12699128888/job/35399094003?pr=33408

AttributeError: 'apache_beam.testing.fast_test_utils.LCGenerator' object has no attribute 'randbytes'