[appservice] "Test Deb Packages Focal" intermittently fails on `test_devops_build_commands_thru_mock.py`

[jiasli]

Describe the bug

"Test Deb Packages Focal" intermittently fails on test_devops_build_commands_thru_mock:

https://dev.azure.com/azure-sdk/public/_build/results?buildId=1133402&view=logs&j=ad51cf76-b294-5bde-777e-be77cc5f3050&t=0e02ab23-4098-514d-f7b9-ab422251bbb2&l=2274

==================================== ERRORS ====================================
____ ERROR collecting tests/latest/test_devops_build_commands_thru_mock.py _____
/opt/az/lib/python3.6/site-packages/azure/cli/command_modules/appservice/tests/latest/test_devops_build_commands_thru_mock.py:10: in <module>
    from azure.cli.command_modules.appservice.azure_devops_build_interactive import (
/opt/az/lib/python3.6/site-packages/azure/cli/command_modules/appservice/azure_devops_build_interactive.py:31: in <module>
    from .azure_devops_build_provider import AzureDevopsBuildProvider
/opt/az/lib/python3.6/site-packages/azure/cli/command_modules/appservice/azure_devops_build_provider.py:7: in <module>
    from azure_functions_devops_build.project.project_manager import ProjectManager
/opt/az/lib/python3.6/site-packages/azure_functions_devops_build/project/project_manager.py:14: in <module>
    from ..base.base_manager import BaseManager
/opt/az/lib/python3.6/site-packages/azure_functions_devops_build/base/base_manager.py:6: in <module>
    from vsts.vss_connection import VssConnection
/opt/az/lib/python3.6/site-packages/vsts/vss_connection.py:9: in <module>
    from ._file_cache import RESOURCE_CACHE as RESOURCE_FILE_CACHE
/opt/az/lib/python3.6/site-packages/vsts/_file_cache.py:122: in <module>
    DEFAULT_CACHE_DIR = get_cache_dir()
/opt/az/lib/python3.6/site-packages/vsts/_file_cache.py:117: in get_cache_dir
    os.makedirs(vsts_cache_dir)
/opt/az/lib/python3.6/os.py:220: in makedirs
    mkdir(name, mode)
E   FileExistsError: [Errno 17] File exists: '/root/.vsts/python-sdk/cache'
---------- generated xml file: /azure_cli_test_result/appservice.xml -----------
=========================== short test summary info ============================
ERROR tests/latest/test_devops_build_commands_thru_mock.py - FileExistsError:...

Log: 419.log

This is due to a bug of vsts that it can't run correctly and fails when racing condition happens. The fix for Yum was made in #18534.

[yonzhan]

appservice

[jiasli]

@panchagnula, I remember vsts is now deprecated. Any chance it can be dropped from CLI or tests?