[GCU] Skip test replace fec, test update speed (sonic-net#8626)

tests/common/plugins/conditional_mark/tests_mark_conditions.yaml

@@ -463,12 +463,10 @@ generic_config_updater/test_ecn_config_update.py::test_ecn_config_updates:
 
 generic_config_updater/test_eth_interface.py::test_replace_fec:
   skip:
-    reason: '1. replace_fec ethernet test is not supported on virtual switch
-             2. Skip on M0 and Mx topo due to DUT interfaces do not support config fec'
-    conditions_logical_operator: OR
+    reason: 'replace_fec ethernet test depends on StateDB values. GCU needs to be updated to consider StateDB'
     conditions:
-      - "platform in ['x86_64-kvm_x86_64-r0']"
-      - "topo_type in ['m0', 'mx'] and https://github.com/sonic-net/sonic-mgmt/issues/8600"
+      - https://github.com/sonic-net/sonic-mgmt/issues/8600
+
 
 generic_config_updater/test_eth_interface.py::test_toggle_pfc_asym:
   skip:
@@ -477,8 +475,8 @@ generic_config_updater/test_eth_interface.py::test_toggle_pfc_asym:
       - "asic_type in ['cisco-8000']"
 
 generic_config_updater/test_eth_interface.py::test_update_speed:
-  xfail:
-    reason: 'Xfail this script due to this not being a production scenario and misleading StateDB output for valid speed'
+  skip:
+    reason: 'Skip this script due to this not being a production scenario and misleading StateDB output for valid speed'
     conditions:
       - https://github.com/sonic-net/sonic-mgmt/issues/8143
 

tests/generic_config_updater/test_eth_interface.py

@@ -205,7 +205,7 @@ def test_toggle_pfc_asym(duthost, ensure_dut_readiness, pfc_asym):
 def test_replace_fec(duthost, ensure_dut_readiness, fec):
     json_patch = [
         {
-            "op": "replace",
+            "op": "add",
             "path": "/PORT/Ethernet0/fec",
             "value": "{}".format(fec)
         }