[Setup] Not skipping conda init

[Michaelvll]

Fixes #2908

This reverts changes in #2277, due to the update of GCP image has resolved the conda init issue in #2273

(Confirmed that the problem exists with the older image we used: sky launch -c test-old-image --cloud gcp --image-id skypilot:cpu-debian-10 'conda activate'. Though it takes longer to launch for older image, but it is not critical for user job.)

Tested (run the relevant ones):

• Code formatting: bash format.sh
• Any manual or new tests for this PR (please specify below)
  • sky launch -c test-aws-conda-init --cloud aws --cpus 2 'conda create -n test -y python=3.8; conda activate test; python --version'; ssh test-aws-conda-init; conda activate; python --version' (check provision.log that there is no error)
  • sky launch -c test-gcp-conda-init --cloud gcp --cpus 2 'conda create -n test -y python=3.8; conda activate test; python --version'; ssh test-gcp-conda-init; conda activate; python --version' (check provision.log that there is no error)
  • sky launch -c test-azure-conda-init --cloud gcp --cpus 2 'conda create -n test -y python=3.8; conda activate test; python --version'; ssh test-azure-conda-init; conda activate; python --version' (check provision.log that there is no error)
• All smoke tests: pytest tests/test_smoke.py
• Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• Backward compatibility tests: bash tests/backward_comaptibility_tests.sh