[multi asic] add ip netns identify command to sudoer (#6591)

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

- Why I did it
The command sudo ip netns identify <pid> is used in function get_current_namespace
to check in the cli command is running in host context or within a namespace.

This function is used for every CLI command and command sudo ip netns identify <pid> needs to be added in sudoer files to allow users with RO access to run show cli commands

This problem is not there on single asic platforms.

- How I did it
Add ip netns identify [0-9]* to sudoers file.

files/image_config/sudoers/sudoers

@@ -35,7 +35,9 @@ Cmnd_Alias      READ_ONLY_CMDS = /bin/cat /var/log/syslog*, \
                                  /usr/local/bin/lldpshow, \
                                  /usr/local/bin/psuutil *, \
                                  /usr/local/bin/sonic-installer list, \
-                                 /usr/local/bin/sfputil show *
+                                 /usr/local/bin/sfputil show *, \
+                                 /bin/ip netns identify [0-9]*
+
 
 Cmnd_Alias      PASSWD_CMDS = /usr/local/bin/config tacacs passkey *, \
                               /usr/sbin/chpasswd *