[show]: Fix show ip route result in "alias" naming mode

[ghost]

• Adding case for "show ip route" command for naming mode
  "alias" to display proper result, instead of json table

Signed-off-by: Maksym Belei Maksym_Belei@jabil.com

- What I did
Resolves sonic-net/sonic-buildimage#6245
Output of command "show ip route" in cases when "naming_mode" is "alias", has fixed.

- How I did it
There is a no condition for "show ip route" command inside function "run_command_in_alias_mode" in https://github.com/Azure/sonic-utilities/blob/master/utilities_common/cli.py#L375.
The condition has added to handle "show ip route" command and return proper output result to the top level modules.

- How to verify it

1. sudo config interface_naming_mode alias
2. show ip route 10.0.0.12

- Previous command output

{
  "10.0.0.12\/31":[
    {
      "prefix":"10.0.0.12\/31",
      "protocol":"connected",
      "selected":true,
      "destSelected":true,
      "distance":0,
      "metric":0,
      "installed":true,
      "table":254,
      "internalStatus":16,
      "internalFlags":8,
      "internalNextHopNum":1,
      "internalNextHopActiveNum":1,
      "uptime":"1d05h50m",
      "nexthops":[
        {
          "flags":3,
          "fib":true,
          "directlyConnected":true,
          "interfaceIndex":475,
          "interfaceName":"Ethernet24",
          "active":true
        }
      ]
    }
  ]
}

- New command output

Routing entry for 10.0.0.12/31
  Known via "connected", distance 0, metric 0, best
  Last update 03:11:50 ago
  * directly connected, etp7

[ghost]

All CLA requirements met.

[ghost]

retest this please

[ghost]

@anshuv-mfst, could I ask you to help me to find somebody who can review this PR?

[pshulik]

@anshuv-mfst, could I ask you to help me to find somebody who can review this PR?