disable pfc_to_queue_map for service port (#24189)

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#### Why I did it
Fix the following error in test:

```
 | File "/usr/local/lib/python3.8/dist-packages/_pytest/outcomes.py", line 198, in fail
 | raise Failed(msg=reason, pytrace=pytrace)
 | Failed: Yang validation failed after config_reload
 +------------------------------------
```
```
29/09/2025 11:38:25 base._run L0108 DEBUG | /var/src/sonic-mgmt_vms91-t0-7060x6-moby-512-3/tests/common/devices/multi_asic.py::_run_on_asics#144: [str5-7060x6-moby-512-3] AnsibleModule::shell Result => {"failed": true, "changed": true, "stdout": "sonic_yang(3):Data Loading Failed:Invalid length for map name.", "stderr": "libyang[0]: Value \"\" does not satisfy the constraint \"1..32\" (range, length, or pattern). (path: /sonic-port-qos-map:sonic-port-qos-map/PORT_QOS_MAP/PORT_QOS_MAP_LIST[ifname='Ethernet512']/pfc_to_queue_map)\nlibyang[0]: Invalid length for map name. (path: /sonic-port-qos-map:sonic-port-qos-map/PORT_QOS_MAP/PORT_QOS_MAP_LIST[ifname='Ethernet512']/pfc_to_queue_map)\nFailed to apply patch due to: Validate json patch: [] failed due to:Data Loading Failed\nInvalid length for map name.\nUsage: config apply-patch [OPTIONS] PATCH_FILE_PATH\nTry \"config apply-patch -h\" for help.\n\nError: Validate json patch: [] failed due to:Data Loading Failed\nInvalid length for map name.", "rc": 2, "cmd": "echo '[]' | sudo config apply-patch /dev/stdin", "start": "2025-09-29 11:38:24.042745", "end": "2025-09-29 11:38:25.165511", "delta": "0:00:01.122766", "msg": "non-zero return code", "invocation": {"module_args": {"_raw_params": "echo '[]' | sudo config apply-patch /dev/stdin", "_uses_shell": true, "warn": false, "stdin_add_newline": true, "strip_empty_ends": true, "argv": null, "chdir": null, "executable": null, "creates": null, "removes": null, "stdin": null}}, "stdout_lines": ["sonic_yang(3):Data Loading Failed:Invalid length for map name."], "stderr_lines": ["libyang[0]: Value \"\" does not satisfy the constraint \"1..32\" (range, length, or pattern). (path: /sonic-port-qos-map:sonic-port-qos-map/PORT_QOS_MAP/PORT_QOS_MAP_LIST[ifname='Ethernet512']/pfc_to_queue_map)", "libyang[0]: Invalid length for map name. (path: /sonic-port-qos-map:sonic-port-qos-map/PORT_QOS_MAP/PORT_QOS_MAP_LIST[ifname='Ethernet512']/pfc_to_queue_map)", "Failed to apply patch due to: Validate json patch: [] failed due to:Data Loading Failed", "Invalid length for map name.", "Usage: config apply-patch [OPTIONS] PATCH_FILE_PATH", "Try \"config apply-patch -h\" for help.", "", "Error: Validate json patch: [] failed due to:Data Loading Failed", "Invalid length for map name."], "_ansible_no_log": null}
29/09/2025 11:38:25 utilities.wait_until L0163 DEBUG | yang_validate is False, wait 30 seconds and check again
29/09/2025 11:38:55 utilities.wait_until L0168 DEBUG | yang_validate is still False after 120 seconds, exit with False
```

##### Work item tracking
- Microsoft ADO **(number only)**:

#### How I did it
Remove `pfc_to_queue_map` for service port.

#### How to verify it

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- [ ] 202205
- [ ] 202211
- [ ] 202305
- [ ] 202311
- [ ] 202405
- [ ] 202411
- [ ] 202505

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#### Link to config_db schema for YANG module changes
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#### A picture of a cute animal (not mandatory but encouraged)

Author: mssonicbld

files/build_templates/qos_config.j2

@@ -455,13 +455,11 @@
 {% endif %}
 {% endif %}
 {% if port not in PORT_DPC %}
-            "tc_to_pg_map"    : "AZURE",
+            "tc_to_pg_map"    : "AZURE"{% if port not in PORT_SERVICE %},{% endif %}
 {% else %}
-            "tc_to_pg_map"    : "AZURE_DPC",
+            "tc_to_pg_map"    : "AZURE_DPC"{% if port not in PORT_SERVICE %},{% endif %}
 {% endif %}
-{% if port in PORT_SERVICE %}
-            "pfc_to_queue_map": ""
-{% else %}
+{% if port not in PORT_SERVICE %}
             "pfc_to_queue_map": "AZURE"
 {% endif %}
         }{% if not loop.last %},{% endif %}

src/sonic-config-engine/tests/sample_output/py3/qos-arista7060x6.json

@@ -1156,14 +1156,12 @@
         "Ethernet512": {
             "dscp_to_tc_map"  : "AZURE",
             "tc_to_queue_map" : "AZURE",
-            "tc_to_pg_map"    : "AZURE",
-            "pfc_to_queue_map": ""
+            "tc_to_pg_map"    : "AZURE"
         },
         "Ethernet513": {
             "dscp_to_tc_map"  : "AZURE",
             "tc_to_queue_map" : "AZURE",
-            "tc_to_pg_map"    : "AZURE",
-            "pfc_to_queue_map": ""
+            "tc_to_pg_map"    : "AZURE"
         }
     },
 "WRED_PROFILE": {