zebra: fix nexthop rib out for duplicate nhg
### **User description**
The duplicate nexthop is not dispalyed with
proper alignment.

```
mlx-4700-44# show nexthop-group rib 580
ID: 580 (zebra)
     RefCnt: 1
     Uptime: 01:39:06
     VRF: default
     Valid, Installed
     Depends: (530) (564) (579)
        via 20.1.1.9 (vrf default) (recursive), weight 1
           via 20.1.1.2, swp1s0 (vrf default), weight 1
        via 30.1.2.9 (vrf default) (recursive), weight 1
           via 30.1.1.2, br_default.60 (vrf default), weight 1
           via 30.1.1.6, vlan70 (vrf default), weight 1
           via 30.1.1.10, bond1 (vrf default), weight 1
           via 20.1.1.2, swp1s0 (vrf default), weight 1 <<<<<<<<
```

Ticket: #4496048

With fix:
```
mlx-4700-44# show nexthop-group rib 580
ID: 580 (zebra)
     RefCnt: 1
     Uptime: 01:39:06
     VRF: default
     Valid, Installed
     Depends: (530) (564) (579)
        via 20.1.1.9 (vrf default) (recursive), weight 1
           via 20.1.1.2, swp1s0 (vrf default), weight 1
        via 30.1.2.9 (vrf default) (recursive), weight 1
           via 30.1.1.2, br_default.60 (vrf default), weight 1
           via 30.1.1.6, vlan70 (vrf default), weight 1
           via 30.1.1.10, bond1 (vrf default), weight 1
        via 20.1.1.2, swp1s0 (vrf default), weight 1

mlx-4700-44# show nexthop-group rib 530
ID: 530 (zebra)
     RefCnt: 17
     Uptime: 02:02:52
     VRF: default
     Valid, Installed
     Interface Index: 38
           via 20.1.1.2, swp1s0 (vrf default), weight 1
     Dependents: (576) (579) (580) (582)

show nexthop-group rib 580 json

  "580":{
    "type":"zebra",
    "refCount":1,
    "uptime":"02:01:33",
    "vrf":"default",
    "nhGrpUptimeEstablishedEpoch":1749708524,
    "valid":true,
    "installed":true,
    "depends":[
      530,
      564,
      579
    ],
    "nexthops":[
      {
        "flags":5,
        "ip":"20.1.1.9",
        "afi":"ipv4",
        "vrf":"default",
        "active":true,
        "recursive":true,
        "weight":1
      },
      {
        "flags":3,
        "fib":true,
        "ip":"20.1.1.2",
        "afi":"ipv4",
        "interfaceIndex":38,
        "interfaceName":"swp1s0",
        "vrf":"default",
        "resolver":true,
        "active":true,
        "weight":1
      },
      {
        "flags":19,
        "duplicate":true, <<<<
        "fib":true,
        "ip":"20.1.1.2",
        "afi":"ipv4",
        "interfaceIndex":38,
        "interfaceName":"swp1s0",
        "vrf":"default",
        "active":true,
        "weight":1
      }
    ]
  }
```

Upstream PR FRRouting#19015


Signed-off-by: Chirag Shah <[email protected]>


___

### **PR Type**
Bug fix


___

### **Description**
- Fix alignment of duplicate nexthops in CLI output


___



### **Changes walkthrough** 📝
<table><thead><tr><th></th><th align="left">Relevant files</th></tr></thead><tbody><tr><td><strong>Bug fix</strong></td><td><table>
<tr>
  <td>
    <details>
      <summary><strong>zebra_vty.c</strong><dd><code>Fix CLI display alignment for duplicate nexthops</code>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </dd></summary>
<hr>

zebra/zebra_vty.c

<li>Added check for NEXTHOP_FLAG_DUPLICATE when determining indentation<br> <li> Applied consistent indentation logic for both regular and backup <br>nexthops<br> <li> Fixed alignment issue where duplicate nexthops were incorrectly <br>indented


</details>


  </td>
  <td><a href="https://gitlab-master.nvidia.com/nbu-sws/CL/FRR/frr/-/blob/chirag/clfrrdev4/zebra/zebra_vty.c?ref_type=heads">+8/-8</a>&nbsp; &nbsp; &nbsp; </td>

</tr>
</table></td></tr></tr></tbody></table>

___

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 #

See merge request nbu-sws/CL/FRR/frr!1160