[consutil][connect] Remove root need from connect line command

[Blueve]

- What I did

Remove root privilege need for consutil connect and show line command.

As discuss in this thread (sonic-net/sonic-buildimage#5438), I am going to remove unnecessary root privilege need from console commands.

- How I did it

• Base on this change ([broadcom][cel][udev] Update console usb devices permission sonic-buildimage#5840), we are safe to remove the root need from consutil command
• Add unit tests for consutil connect command

- How to verify it

Build py-wheel package and install+test on a physical SONiC DUT

- Previous command output (if the output of a command-line utility has changed)

admin@sonic:~$ consutil connect 1
Root privileges are required for this operation

- New command output (if the output of a command-line utility has changed)

admin@sonic:~$ consutil connect 1
Successful connection to line [1]
Press ^A ^X to disconnect