T6267: Check interface wireless module before apply config

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'
```

src/conf_mode/interfaces_wireless.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2020 VyOS maintainers and contributors
+# Copyright (C) 2019-2024 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -31,8 +31,9 @@
 from vyos.configverify import verify_bond_bridge_member
 from vyos.ifconfig import WiFiIf
 from vyos.template import render
-from vyos.utils.process import call
 from vyos.utils.dict import dict_search
+from vyos.utils.kernel import check_kmod
+from vyos.utils.process import call
 from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
@@ -118,6 +119,10 @@ def verify(wifi):
     if 'physical_device' not in wifi:
         raise ConfigError('You must specify a physical-device "phy"')
 
+    physical_device = wifi['physical_device']
+    if not os.path.exists(f'/sys/class/ieee80211/{physical_device}'):
+        raise ConfigError(f'Wirelss interface PHY "{physical_device}" does not exist!')
+
     if 'type' not in wifi:
         raise ConfigError('You must specify a WiFi mode')
 
@@ -266,6 +271,7 @@ def apply(wifi):
 
 if __name__ == '__main__':
     try:
+        check_kmod('mac80211')
         c = get_config()
         verify(c)
         generate(c)