[action] [PR:12510] [pretest] Testcase to validate backend acl load

[mssonicbld]

Description of PR

Summary:
Fixes #12048

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 201911
• 202012
• 202205
• 202305
• 202311

Approach

What is the motivation for this PR?

Add an explicit testcase to validate that acl is loaded successfully on the backend T0 testbed. Without this case, acl load failure was determined by examining the nighly run failures on the backend testbed

How did you verify/test it?

Ran the test against a backend T0 testbed with the fix to load acl correctly and it passed
Ran the test against a non backend T0 testbed and it is skipped

test_pretest.py::test_features_state[str2-7050qx-32s-acs-02] PASSED [ 7%]
test_pretest.py::test_cleanup_testbed[str2-7050qx-32s-acs-02] PASSED [ 14%]
test_pretest.py::test_disable_container_autorestart[str2-7050qx-32s-acs-02] PASSED [ 21%]
test_pretest.py::test_disable_rsyslog_rate_limit[str2-7050qx-32s-acs-02] PASSED [ 28%]
test_pretest.py::test_connect_to_internal_nameserver[str2-7050qx-32s-acs-02] PASSED [ 35%]
test_pretest.py::test_update_buffer_template[str2-7050qx-32s-acs-02] PASSED [ 42%]
test_pretest.py::test_backend_acl_load[str2-7050qx-32s-acs-02] PASSED [ 50%]
test_pretest.py::test_cleanup_cache PASSED [ 57%]
test_pretest.py::test_update_testbed_metadata 
--------------------------------------------------------------- live log call ----------------------------------------------------------------
19:55:47 test_pretest.prepare_autonegtest_params L0358 WARNING| skipped to create autoneg test datafile because of no ports selected
PASSED [ 64%]
test_pretest.py::test_collect_testbed_prio PASSED [ 71%]
test_pretest.py::test_collect_pfc_pause_delay_params PASSED [ 78%]
test_pretest.py::test_update_saithrift_ptf SKIPPED (No URL specified for python saithrift package) [ 85%]
test_pretest.py::test_conn_graph_valid PASSED [ 92%]
test_pretest.py::test_generate_running_golden_config PASSED [100%]


test_pretest.py::test_backend_acl_load[str2-7050qx-32s-acs-03] SKIPPED (Skip 'test_backend_acl_load' on non t0-backend testbeds.) [100%]

Supported testbed topology if it's a new test case?

t0-backend

[mssonicbld]

Original PR: #12510