[show/tests] Add support for "show run isis"

[isabelladeleon12]

Signed-off-by: ideleon@microsoft.com

What I did

How I did it

How to verify it

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)

admin@vlab-01:/usr/local/lib/python3.9/dist-packages/show$ show run isis
Building configuration...

Current configuration:
!
frr version 8.2.2
frr defaults traditional
hostname vlab-01
log syslog informational
log facility local4
no service integrated-vtysh-config
!
password zebra
enable password zebra
!
interface PortChannel101
 ip router isis 1
 ipv6 router isis 1
 isis network point-to-point
exit
!
router isis 1
 is-type level-2-only
 net 49.0001.1720.1700.0002.00
 lsp-mtu 1383
 lsp-timers level-1 gen-interval 30 refresh-interval 900 max-lifetime 1200
 lsp-timers level-2 gen-interval 30 refresh-interval 305 max-lifetime 900
 log-adjacency-changes
exit
!
end

admin@vlab-01:/usr/local/lib/python3.9/dist-packages/show$ show run isis --config_db
{
    "ISIS_GLOBAL": {
        "1": {
            "dynamic-hostname": "true",
            "level-capability": "level-2",
            "log-adjacency-changes": "true",
            "lsp-mtu-size": "1383",
            "net": "49.0001.1720.1700.0002.00"
        }
    },
    "ISIS_LEVEL": {
        "1|level-2": {
            "lsp-maximum-lifetime": "350",
            "lsp-refresh-interval": "305"
        }
    },
    "ISIS_INTERFACE": {
        "1|PortChannel101": {
            "hello-padding": "false",
            "ifname": "PortChannel101",
            "instance": "1",
            "ipv4-routing-instance": "1",
            "ipv6-routing-instance": "1",
            "network-type": "POINT_TO_POINT_NETWORK"
        }
    }
}
admin@vlab-01:/usr/local/lib/python3.9/dist-packages/show$