feat(neutron): Reparent Palo Alto stub router flavor to base service plugin class PUC-1760

[nidzrai]

Reparent Palo Alto stub router flavor to base service plugin class

Test result on iad-dev:

~ 🐍 openstack on ☁️  uc-dev-infra(baremetal) took 4s
❯ openstack router show nidhi-palo-router
+---------------------------+--------------------------------------+
| Field                     | Value                                |
+---------------------------+--------------------------------------+
| admin_state_up            | UP                                   |
| availability_zone_hints   |                                      |
| availability_zones        |                                      |
| created_at                | 2026-07-10T09:00:02Z                 |
| description               |                                      |
| enable_default_route_bfd  | False                                |
| enable_default_route_ecmp | False                                |
| enable_ndp_proxy          | None                                 |
| enable_snat               | True                                 |
| evpn_vni                  | 5                                    |
| external_gateway_info     | null                                 |
| external_gateways         | []                                   |
| flavor_id                 | 3769f27b-1c13-4f06-8acd-f5a65547df06 |
| ha                        | False                                |
| id                        | a94b3600-195a-4fa8-93dd-eaa0b41b7679 |
| interfaces_info           | []                                   |
| name                      | nidhi-palo-router                    |
| project_id                | 32e02632f4f04415bab5895d1e7247b7     |
| revision_number           | 1                                    |
| routes                    |                                      |
| status                    | ACTIVE                               |
| tags                      |                                      |
| updated_at                | 2026-07-10T09:00:02Z                 |
+---------------------------+--------------------------------------+
(openstack)
~ 🐍 openstack on ☁️  uc-dev-infra(baremetal) took 4s
❯ openstack router show nidhi-palo-router-after-code
+---------------------------+--------------------------------------+
| Field                     | Value                                |
+---------------------------+--------------------------------------+
| admin_state_up            | UP                                   |
| availability_zone_hints   |                                      |
| availability_zones        |                                      |
| created_at                | 2026-07-14T11:17:27Z                 |
| description               |                                      |
| enable_default_route_bfd  | False                                |
| enable_default_route_ecmp | False                                |
| enable_ndp_proxy          | None                                 |
| enable_snat               | True                                 |
| evpn_vni                  | 6                                    |
| external_gateway_info     | null                                 |
| external_gateways         | []                                   |
| flavor_id                 | 3769f27b-1c13-4f06-8acd-f5a65547df06 |
| ha                        | False                                |
| id                        | 1fb702ba-91a9-4307-b407-a268ab3da275 |
| interfaces_info           | []                                   |
| name                      | nidhi-palo-router-after-code         |
| project_id                | 32e02632f4f04415bab5895d1e7247b7     |
| revision_number           | 1                                    |
| routes                    |                                      |
| status                    | ACTIVE                               |
| tags                      |                                      |
| updated_at                | 2026-07-14T11:17:27Z                 |
+---------------------------+--------------------------------------+
(openstack)
~ 🐍 openstack on ☁️  uc-dev-infra(baremetal) took 5s
❯