Vnet_name added in create_only patterns (#3878)

What I did
Added support to mark the vnet_name field as a create-only field in VLAN_INTERFACE, VLAN_SUB_INTERFACE, and INTERFACE tables.

How I did it
Updated patch_sorter.py to include the following patterns as create-only fields:
["VLAN_SUB_INTERFACE", "*", "vnet_name"],
["VLAN_INTERFACE", "*", "vnet_name"],
["INTERFACE", "*", "vnet_name"]
Added test data in patch_sorter_test.py to verify these fields are identified as create-only.
Updated change_applier_test.data.json with example entries containing vnet_name fields.
Added unit tests in patch_sorter_test_success.json for test_patch_sorter_success in patch_sorter_test.py

Author: miatttao

generic_config_updater/patch_sorter.py

@@ -571,6 +571,9 @@ def __init__(self, path_addressing):
             ["BGP_MONITORS", "*", "nhopself"],
             ["BGP_MONITORS", "*", "rrclient"],
             ["MIRROR_SESSION", "*", "*"],
+            ["VLAN_SUB_INTERFACE", "*", "vnet_name"],
+            ["VLAN_INTERFACE", "*", "vnet_name"],
+            ["INTERFACE", "*", "vnet_name"],
         ]
 
     def get_filter(self):

tests/generic_config_updater/files/change_applier_test.data.json

@@ -136,6 +136,11 @@
                 "type": "LeafRouter"
             }
         },
+        "INTERFACE": {
+            "Ethernet2": {
+                "vnet_name": "Vnet3"
+            }
+        },
         "PORT": {
             "Ethernet0": {
                 "alias": "fortyGigE0/0",
@@ -232,7 +237,10 @@
         "VLAN_INTERFACE": {
             "Vlan1000": {},
             "Vlan1000|192.168.0.1/21": {},
-            "Vlan1000|2603:10b0:b13:c70::1/64": {}
+            "Vlan1000|2603:10b0:b13:c70::1/64": {},
+            "Vlan100": {
+                "vnet_name": "Vnet2"
+            }
         },
         "VLAN_MEMBER": {
             "Vlan1000|Ethernet12": {
@@ -244,6 +252,12 @@
             "Vlan1000|Ethernet28": {
             }
         },
+        "VLAN_SUB_INTERFACE": {
+            "Ethernet0.10": {
+                "vlan": 10,
+                "vnet_name": "Vnet1"
+            }
+        },
         "WRED_PROFILE": {
             "AZURE_LOSSLESS": {
                 "ecn": "ecn_all",