Remove TF SE nightly ResNet and Keras

[RissyRan]

Description

Remove TF SE nightly ResNet and Keras, as we have onboarded to Airflow:

• Keras on v2-8
• ResNet on v2-8, v2-32, v3-8, v3-23, v4-8, and v4-32

Tests

Please describe the tests that you ran on TPUs to verify changes.

Instruction and/or command lines to reproduce your tests: ...
N/A

List links for your tests (use go/shortn-gen for any internal link): ...

• ./scripts/gen-tests.sh passed, and has dlrm tests only

k8s/europe-west4/gen/pt-nightly-resnet50-pjrt-fake-v3-32-1vm.yaml
k8s/us-central2/gen/tf.se.nightly-dlrm-criteo-func-v4-8-1vm.yaml

• Checks are all passed.

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run one-shot tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed.

[EricLeFort]

Thanks Ran!