CLI test runs slowly

[bebound]

As described in #30238

There two known issues in the CLI test that reduce speed improvement when using a multi-core agent:

1. Some modules are run in serial, such as network.
2. Some tests run much slower than others, slowing down the entire testing process. For example: tests/latest/test_keyvault_commands.py::KeyVaultMgmtScenarioTest::test_keyvault_list_deleted takes 6 min.

[yonzhan]

Thank you for opening this issue, we will look into it.

[bebound]

replace by #30923