Bug: bgp/test_bgp_bounce.py ipv6-only not supported

[yanmo96]

Is it platform specific

generic

Importance or Severity

Medium

Description of the bug

The test do not support to get ipv6 bgp community no-export from eos

        # Take action on one of the ToR VM
>       no_export_route_num = get_no_export_output(vm_host)

backup_bgp_config = None
bgp_no_export_config = 'tmp/bgp/bgp_no_export.j2'
bgp_plain_config = 'tmp/bgp/bgp_plain.j2'
deploy_no_export_bgp_config = 'tmp/bgp/bgp_no_export.j2'
deploy_plain_bgp_config = 'tmp/bgp/bgp_plain.j2'
duthost    = <MultiAsicSonicHost str4-7060x6-512-7>
nbrhosts   = {'ARISTA01T0': <EosHost VM75429>, 'ARISTA01T2': <EosHost VM75441>, 'ARISTA09T0': <EosHost VM75430>, 'ARISTA105T0': <EosHost VM75443>, ...}
vm_host    = <EosHost VM75474>
vm_name    = 'ARISTA353T0'

bgp/test_bgp_bounce.py:51: 
```s 

### Steps to Reproduce

Run:
`yanmo@sonic-mgmt-yanmo:/var/src/sonic-mgmt-int/tests$ ./run_tests.sh -m individual -a False  -e '--skip_sanity --disable_loganalyzer' -c bgp/test_bgp_bounce.py -n vms75-t1-7060x6-7 -i  ../ansible/str4,../ansible/veos -q 1 -u`

### Actual Behavior and Expected Behavior

Expected to pass on ipv6 only testbed.

### Relevant log output

```shell

Output of show version

Attach files (if any)

No response