chore: fixing get_interfaces() to support interfaces without line pro…

[humbertogaliza]

This PR is to adjust logic to support interfaces without "Line Protocol" in the "display interfaces" output, for example, Virtual-Ethernet interfaces configured in layer-2 mode. Example:

Subtask: napalm_get (failed)

---- napalm_get ** changed : False --------------------------------------------- ERROR
Traceback (most recent call last):
  File "/Users/hgaliza/Library/Caches/pypoetry/virtualenvs/remessa-FeQPNv6p-py3.11/lib/python3.11/site-packages/nornir/core/task.py", line 99, in start
    r = self.task(self, **self.params)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/hgaliza/Library/Caches/pypoetry/virtualenvs/remessa-FeQPNv6p-py3.11/lib/python3.11/site-packages/nornir_napalm/plugins/tasks/napalm_get.py", line 44, in napalm_get
    result[g] = method(**options)
                ^^^^^^^^^^^^^^^^^
  File "/Users/hgaliza/workspace/napalm-huawei-vrp/napalm_huawei_vrp/huawei_vrp.py", line 623, in get_interfaces
    raise ValueError(msg)
ValueError: Unexpected interface format: Virtual-Ethernet0/0/1 current state : UP
Description:
Route Port,The Maximum Transmit Unit is 1500
Internet protocol processing : disabled
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is c4e2-8720-b160
Current system time: 2024-06-15 07:51:39-03:00
    Input bandwidth utilization  :    0%
    Output bandwidth utilization :    0%

Interface configuration, for reference:

dis cur int Virtual-Ethernet 0/0/1
#
interface Virtual-Ethernet0/0/1
 ve-group 1 l2-terminate
#

After this fix:

---- napalm_get ** changed : False --------------------------------------------- INFO
{ 'get_interfaces': { 'Virtual-Ethernet0/0/1': { 'description': '',
                                                 'is_enabled': True,
                                                 'is_up': False,
                                                 'last_flapped': -1.0,
                                                 'mac_address': 'C4:E2:87:20:B1:60',
                                                 'mtu': 1500,
                                                 'speed': -1.0},
(...)