[UT] Fix 'get_device_interface_naming_mode' mock not taking effect (#341

)

* [UT] Clear intf_naming_mode in utils

* Resolve sanity failures

tests/unit/modules/network/sonic/sonic_module.py

@@ -4,6 +4,9 @@
 import os
 import yaml
 
+from ansible_collections.dellemc.enterprise_sonic.tests.unit.compat.mock import (
+    patch,
+)
 from ansible_collections.dellemc.enterprise_sonic.tests.unit.modules.utils import (
     AnsibleExitJson,
     AnsibleFailJson,
@@ -23,13 +26,21 @@ class TestSonicModule(ModuleTestCase):
 
     def setUp(self):
         super(TestSonicModule, self).setUp()
+        self.mock_utils_intf_naming_mode = patch(
+            "ansible_collections.dellemc.enterprise_sonic.plugins.module_utils.network.sonic.utils.utils.intf_naming_mode", ""
+        )
+        self.mock_utils_intf_naming_mode.start()
 
         self.config_requests_valid = []
         self.config_requests_sent = []
 
         self._config_requests_dict = {}
         self._facts_requests_dict = {}
 
+    def tearDown(self):
+        super(TestSonicModule, self).tearDown()
+        self.mock_utils_intf_naming_mode.stop()
+
     @staticmethod
     def load_fixtures(file_name, content="yaml"):
         """Load data from specified fixture file and format"""