remove test case for slug character conversion

This scenario is now unsupported

Author: mabezi

tests/unit/module_utils/test_data/netbox_utils/normalize_data.json

@@ -215,14 +215,6 @@
             "prefix_role": "test-role-1"
         }
     },
-    {
-        "before": {
-            "slug": "Test to_slug"
-        },
-        "after": {
-            "slug": "test-to_slug"
-        }
-    },
     {
         "before": {
             "tenant": "Test Tenant"
@@ -345,4 +337,4 @@
             "mac_address": "AA:BB:CC:DD:EE:FF"
         }
     }
-]
+]