Fix test_reload_config issue: sonic-net#11654 (sonic-net#11674)

1. Revert PR: sonic-net#7289, because the relevant issue has been fixed by PR:sonic-net/sonic-buildimage#15080
2. Remove  wait_until(60, 1, 0, check_interfaces_config_service_status, duthost) in PR: sonic-net#7953 due to the above same reason

Author: JibinBao

tests/platform_tests/test_reload_config.py

@@ -7,7 +7,6 @@
 import logging
 
 import pytest
-import re
 
 from tests.common.fixtures.conn_graph_facts import conn_graph_facts     # noqa F401
 from tests.common.utilities import wait_until
@@ -125,9 +124,6 @@ def test_reload_configuration_checks(duthosts, enum_rand_one_per_hwsku_hostname,
     # we must give it a little longer or else it may falsely fail the test.
     wait_until(360, 1, 0, check_database_status, duthost)
 
-    # Check if interfaces-config.service is exited
-    wait_until(60, 1, 0, check_interfaces_config_service_status, duthost)
-
     logging.info("Reload configuration check")
     out = duthost.shell("sudo config reload -y",
                         executable="/bin/bash", module_ignore_errors=True)
@@ -145,8 +141,6 @@ def test_reload_configuration_checks(duthosts, enum_rand_one_per_hwsku_hostname,
     logging.info("Checking config reload after system is up")
     # Check if all database containers have started
     wait_until(60, 1, 0, check_database_status, duthost)
-    # Check if interfaces-config.service is exited
-    wait_until(60, 1, 0, check_interfaces_config_service_status, duthost)
     out = duthost.shell("sudo config reload -y",
                         executable="/bin/bash", module_ignore_errors=True)
     assert "Retry later" in out['stdout']
@@ -170,11 +164,3 @@ def test_reload_configuration_checks(duthosts, enum_rand_one_per_hwsku_hostname,
     assert "Retry later" not in out['stdout']
 
     assert wait_until(300, 20, 0, config_system_checks_passed, duthost, delayed_services)
-
-
-def check_interfaces_config_service_status(duthost):
-    # check interfaces-config.service status
-    regx_interface_config_service_exit = r'.*Main PID: \d+ \(code=exited, status=0\/SUCCESS\).*'
-    interface_config_server_status = duthost.command(
-        'systemctl status interfaces-config.service', module_ignore_errors=True)['stdout']
-    return re.search(regx_interface_config_service_exit, interface_config_server_status)