Add k8s join and disjoin test cases (#16141)#16364

bingwang-ms merged 4 commits intosonic-net:202405sonic-net/sonic-mgmt:202405from

lixiaoyuner:dev/yunli1/202405-cherry-pick-k8s-join-caselixiaoyuner/sonic-mgmt:dev/yunli1/202405-cherry-pick-k8s-join-caseCopy head branch name to clipboard