T6267: Check interface wireless module before apply config (backport #3368)

[mergify]

Change Summary

Check if the wireless device/modem exists in the system and the module ieee802111 was loaded
In cases where we do not have wireless devices, it prevents the unexpected traceback

set interfaces wireless wlan0 address 192.0.2.5/32
commit

Traceback (most recent call last):
  File "/usr/libexec/vyos/conf_mode/interfaces_wireless.py", line 269, in <modu>
    c = get_config()
        ^^^^^^^^^^^^
  File "/usr/libexec/vyos/conf_mode/interfaces_wireless.py", line 104, in get_cg
    tmp = find_other_stations(conf, base, wifi['ifname'])
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/libexec/vyos/conf_mode/interfaces_wireless.py", line 54, in find_os
    for phy in os.listdir('/sys/class/ieee80211'):
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/ieee80211'

(I do not have an actual wireless device to check if it will work when the device really exists, will be perfect to re-check it)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T6267

Related PR(s)

Component(s) name

wireless

Proposed changes

How to test

In the instance without a wireless device try to configure a wireless interface:

set interfaces wireless wlan0 address 192.0.2.5/32
commit

Before the fix:

Traceback (most recent call last):
  File "/usr/libexec/vyos/conf_mode/interfaces_wireless.py", line 269, in <modu>
    c = get_config()
        ^^^^^^^^^^^^
  File "/usr/libexec/vyos/conf_mode/interfaces_wireless.py", line 104, in get_cg
    tmp = find_other_stations(conf, base, wifi['ifname'])
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/libexec/vyos/conf_mode/interfaces_wireless.py", line 54, in find_os
    for phy in os.listdir('/sys/class/ieee80211'):
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/ieee80211'

After the fix:

vyos@r4# commit
[ interfaces wireless wlan0 ]
Wireless module is not found!

[[interfaces wireless wlan0]] failed
Commit failed
[edit]
vyos@r4# 

Smoketest result

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

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This is an automatic backport of pull request #3368 done by [Mergify](https://mergify.com).