get_bgp_neighbors() fails when there are Peers with same IP on different VRFs, works fine if they are unique.

[sohanrai09]

Description of Issue/Question

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Did you follow the steps from https://github.com/napalm-automation/napalm#faq

(Place an x between the square brackets where applicable)

• [x] Yes
• [] No

Setup

napalm version

(Paste verbatim output from pip freeze | grep napalm between quotes below)

napalm==3.3.1

Network operating system version

(Paste verbatim output from show version - or equivalent - between quotes below)

IOSv Software (VIOS-ADVENTERPRISEK9-M), Version 15.6(2)T, RELEASE SOFTWARE (fc2)

Steps to Reproduce the Issue

get_bgp_neighbors() fails when there are Peers with same IP on different VRFs, works fine if they are unique

Config :
R-2#sh run | s r b
router bgp 200
bgp log-neighbor-changes
neighbor 12.12.12.1 remote-as 100
!
address-family vpnv4
exit-address-family
!
address-family ipv4 vrf VRF-1
neighbor 20.20.20.1 remote-as 100
neighbor 20.20.20.1 timers 10 30
neighbor 20.20.20.1 activate
neighbor 30.30.30.1 remote-as 100
neighbor 30.30.30.1 timers 10 30
neighbor 30.30.30.1 activate
exit-address-family
!
address-family ipv4 vrf VRF-2
neighbor 20.20.20.1 remote-as 100
neighbor 20.20.20.1 timers 10 30
neighbor 20.20.20.1 activate
exit-address-family
R-2#

CLI BGP O/P (shortened):
R-2#sh ip bgp all summ
For address family: IPv4 Unicast
==omitted==

        Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
        12.12.12.1      4        100      48      50        2    0    0 00:07:25        1
        
        For address family: VPNv4 Unicast
        ==omitted==
        
        Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
        20.20.20.1      4        100       0       0        1    0    0 never    Idle
        20.20.20.1      4        100      49      51        3    0    0 00:07:22        1
        30.30.30.1      4        100      50      51        3    0    0 00:07:23        1
        R-2#

Error Traceback

(Paste the complete traceback of the exception between quotes below)

Traceback (most recent call last):
  File "c:\Users\User\Documents\Python\test2.py", line 10, in <module>
    BGP = device.get_bgp_neighbors()
  File "C:\Users\User\AppData\Local\Programs\Python\Python39\lib\site-packages\napalm\ios\ios.py", line 1903, in get_bgp_neighbors
    assert afi not in existing["address_family"]
AssertionError

[jtishey]

Submitted PR #1751 for review to fix this.