[action] [PR:15411] bgp/test_bgp_session_flap.py Fix condition intended to skip iBGP neighbors to work on single-asic

[mssonicbld]

Description of PR

#13662 added support for running bgp/test_bgp_session_flap.py on T2 topology.
However, the condition it added to skip iBGP neighbors only works on multi-asic LCs:
if 'asic' not in v['description'].lower():

E.G. here is a switch which has 3 LCs (LC4 - multi-asic, LC5 - multi-asic, LC6 - single-asic)

root@cmp206-4:~# show ip bgp summary -d all
...
Neighbhor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd NeighborName
----------- --- ----- --------- --------- -------- ----- ------ --------- -------------- --------------
10.0.0.1 4 65200 4113 6364 0 0 0 01:21:00 34050 ARISTA01T3
...
10.0.0.63 4 65200 4033 6720 0 0 0 01:19:44 34050 ARISTA32T3
10.0.254.1 4 65100 20415 27839 0 0 0 02:09:35 340512 ASIC0
10.0.254.3 4 65100 27839 20415 0 0 0 02:09:34 476708 ASIC1
10.0.254.5 4 65100 4737 23014 0 0 0 01:33:32 2067 cmp206-5-ASIC0
10.0.254.5 4 65100 4738 31515 0 0 0 01:33:33 2067 cmp206-5-ASIC0
10.0.254.7 4 65100 5803 27835 0 0 0 02:09:27 4131 cmp206-5-ASIC1
10.0.254.7 4 65100 5844 20415 0 0 0 02:09:34 4131 cmp206-5-ASIC1
10.0.254.9 4 65100 7197 20394 0 0 0 02:09:01 6196 cmp206-6
10.0.254.9 4 65100 7197 26987 0 0 0 02:09:03 6196 cmp206-6

Note that LC4 and LC5 neighbor iBGPs will be skipped because ASIC is in the name but LC6 won't because it's single ASIC.

The better solution is to check the BGP session's peer group which will indicate if it's internal or not regardless of single-asic or multi-asic

Neighbhor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd NeighborName
----------- --- ----- --------- --------- -------- ----- ------ --------- -------------- --------------
10.0.254.1 4 65100 6818 6818 0 0 0 03:10:58 68104 ASIC0
10.0.254.5 4 65100 5731 7122 0 0 0 02:35:12 1037 cmp314-4

(Pdb) bgp_facts['bgp_neighbors']['10.0.254.5']
{'admin': 'up', 'accepted prefixes': 7, 'ip_version': 4, 'remote AS': 65100, 'local AS': 65100, 'description': 'cmp314-4', 'peer group': 'VOQ_CHASSIS_V4_PEER', 'remote routerid': '8.0.0.7', 'state': 'established', 'capabilities': {'peer restart timer': 120}, 'message statistics': {'Opens': {'sent': 3, 'rcvd': 3}, 'Notifications': {'sent': 0, 'rcvd': 0}, 'Updates': {'sent': 1634, 'rcvd': 243}, 'Keepalives': {'sent': 2373, 'rcvd': 2373}, 'Route Refresh': {'sent': 0, 'rcvd': 0}, 'Capability': {'sent': 0, 'rcvd': 0}, 'Total': {'sent': 4010, 'rcvd': 2619}}, 'mrai': 0, 'connections established': 3, 'connections dropped': 2}
(Pdb) bgp_facts['bgp_neighbors']['10.0.254.1']
{'admin': 'up', 'accepted prefixes': 4, 'ip_version': 4, 'remote AS': 65100, 'local AS': 65100, 'description': 'ASIC0', 'peer group': 'VOQ_CHASSIS_V4_PEER', 'remote routerid': '8.0.0.2', 'state': 'established', 'capabilities': {'peer restart timer': 120}, 'message statistics': {'Opens': {'sent': 1, 'rcvd': 1}, 'Notifications': {'sent': 0, 'rcvd': 0}, 'Updates': {'sent': 1088, 'rcvd': 1088}, 'Keepalives': {'sent': 2612, 'rcvd': 2612}, 'Route Refresh': {'sent': 0, 'rcvd': 0}, 'Capability': {'sent': 0, 'rcvd': 0}, 'Total': {'sent': 3701, 'rcvd': 3701}}, 'mrai': 0, 'connections established': 1, 'connections dropped': 0}

Note: I included INTERNAL as another keyword to indicate an iBGP neighbor as I believe that's what non-voq chassis will have as their neighbor name (Took this from https://github.com/sonic-net/sonic-mgmt/blob/master/tests/bgp/test_bgp_queue.py#L64)

Summary:
Fixes #15410

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405

[mssonicbld]

Original PR: #15411