[cli][bgp]use vtysh in the show ip bgp summary command (#1137)

Signed-off-by: Arvindsrinivasan Lakshmi Narasimhan <arlakshm@microsoft.com>

Modify the run_bgp_command function to call vtysh with correct instance_id and vtysh cmd.
The vtysh script is modified to take the namespace id in this PR sonic-net/sonic-buildimage#5479

utilities_common/bgp_util.py

@@ -154,9 +154,9 @@ def run_bgp_command(vtysh_cmd, bgp_namespace=multi_asic.DEFAULT_NAMESPACE):
     bgp_instance_id = ' '
     output = None
     if bgp_namespace is not multi_asic.DEFAULT_NAMESPACE:
-        bgp_instance_id = multi_asic.get_asic_id_from_name(bgp_namespace)
+        bgp_instance_id = " -n {} ".format(multi_asic.get_asic_id_from_name(bgp_namespace))
 
-    cmd = 'sudo docker exec bgp{} vtysh -c "{}"'.format(
+    cmd = 'sudo vtysh {} -c "{}"'.format(
         bgp_instance_id, vtysh_cmd)
     try:
         output = clicommon.run_command(cmd, return_cmd=True)