[Azure] Avoid azure reconfig everytime, speed up launch by up to 5.8x

[Michaelvll]

Mitigates #3695.

This PR avoids an additional configuration which causes a significant slow down.

Single Node (1.6x faster)

multitme -n 5 sky launch --cloud azure -y
            Mean        Std.Dev.    Min         Median      Max
real        214.837     11.941      203.255     211.937     237.772
user        9.281       0.455       8.990       9.093       10.186
sys         2.748       0.080       2.641       2.761       2.873

Single Node on existing cluster (5.8x faster)

multitime -n 5 sky launch -c test-azure-skip-deploy --cloud azure --cpus 2 -y
            Mean        Std.Dev.    Min         Median      Max
real        28.327      0.950       27.159      28.309      29.676      
user        10.261      0.166       10.113      10.187      10.582      
sys         1.497       0.066       1.442       1.472       1.623 

Multi Node (1.24x faster)

multitime -n 5 sky launch --cloud azure -y --cpus 2 --num-nodes 2
            Mean        Std.Dev.    Min         Median      Max
real        541.261     284.335     385.725     402.150     1109.727
user        21.173      2.179       19.834      19.920      25.469
sys         5.746       0.293       5.519       5.640       6.322

Tested (run the relevant ones):

• Code formatting: bash format.sh
• Any manual or new tests for this PR (please specify below)
  • sky autostop -i 0 --down test-azure
  • Wait until the cluster terminated, and sky launch -c test-azure echo hi
  • sky launch -c test-azure --cloud azure --cpus 2 echo hi; manually terminate the cluster; sky down test-azure
  • sky launch -c test-azure --cloud azure --cpus 2 echo hi; manually delete resource group on the portal; sky stop test-azure (our error handling works)
• All smoke tests: pytest tests/test_smoke.py --azure (except for tests related to GPUs due to the quota limit and the issue with A10 [Core] Fix A10 GPU on Azure #3707)

FAILED tests/test_smoke.py::test_managed_jobs - Exception: test failed: less /var/tmp/managed-jobs-i8368hll.log
FAILED tests/test_smoke.py::test_skyserve_large_readiness_timeout - Exception: test failed: less /var/tmp/test-skyserve-large-readiness-timeout-xcoph374.log
FAILED tests/test_smoke.py::test_huggingface - Exception: test failed: less /var/tmp/huggingface_glue_imdb_app-fool8shv.log
FAILED tests/test_smoke.py::test_multi_echo - Exception: test failed: less /var/tmp/multi_echo-sz1vyxl_.log
FAILED tests/test_smoke.py::test_job_queue - Exception: test failed: less /var/tmp/job_queue-51ns08vv.log
FAILED tests/test_smoke.py::test_job_queue_with_docker[docker:continuumio/miniconda3:latest] - Exception: test failed: less /var/tmp/job_queue_with_docker-4m7keo3r.log
FAILED tests/test_smoke.py::test_cancel_pytorch - Exception: test failed: less /var/tmp/cancel-pytorch-w43a0mbm.log
FAILED tests/test_smoke.py::test_job_queue_with_docker[docker:nvidia/cuda:11.8.0-devel-ubuntu18.04] - Exception: test failed: less /var/tmp/job_queue_with_docker-bxu6ez58.log
FAILED tests/test_smoke.py::test_job_queue_with_docker[docker:ubuntu:18.04] - Exception: test failed: less /var/tmp/job_queue_with_docker-q6o1kwco.log
FAILED tests/test_smoke.py::test_job_queue_with_docker[docker:winglian/axolotl:main-latest] - Exception: test failed: less /var/tmp/job_queue_with_docker-e0xabtb2.log
FAILED tests/test_smoke.py::test_sky_bench - Exception: test failed: less /var/tmp/sky-bench-exgbfdgp.log
FAILED tests/test_smoke.py::test_job_queue_multinode - Exception: test failed: less /var/tmp/job_queue_multinode-cd29qwwe.log
FAILED tests/test_smoke.py::test_job_queue_with_docker[docker:continuumio/miniconda3:24.1.2-0] - Exception: test failed: less /var/tmp/job_queue_with_docker-n1agtcv7.log
FAILED tests/test_smoke.py::test_skyserve_readiness_timeout_fail - Exception: test failed: less /var/tmp/test-skyserve-readiness-timeout-fail-y1wcupuq.log
FAILED tests/test_smoke.py::test_skyserve_base_ondemand_fallback - Exception: test failed: less /var/tmp/test-skyserve-base-ondemand-fallback-h887u0t1.log
FAILED tests/test_smoke.py::test_skyserve_update - Exception: test failed: less /var/tmp/test-skyserve-update-wigafrh6.log
FAILED tests/test_smoke.py::test_skyserve_llm - Exception: test failed: less /var/tmp/test-skyserve-llm-smothj9l.log
FAILED tests/test_smoke.py::test_skyserve_new_autoscaler_update[blue_green] - Exception: test failed: less /var/tmp/test-skyserve-new-autoscaler-update-5pof25gf.log
FAILED tests/test_smoke.py::test_skyserve_new_autoscaler_update[rolling] - Exception: test failed: less /var/tmp/test-skyserve-new-autoscaler-update-kg7w6usv.log

• Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• Backward compatibility tests: conda deactivate; bash -i tests/backward_compatibility_tests.sh

[cblmemo]

Thanks for fixing this @Michaelvll ! LGTM.