Fix mirror cli validation for source port list

[rupesh-k]

What I did

Fix CLI validation for source ports in mirror session Fixed issue https://github.com/sonic-net/sonic-buildimage/issues/16604

How I did it

Modify re.search to check individual ports

How to verify it

Failed test

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

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