Add extra check for ESSID field in case there's a wired connection

[Zepheus]

Description:

Unifi controller also manages non-wireless connections for which an essid field is not present. This will skip these hosts when an ssid filter is present.

Related issue: fixes #13366

Pull request in home-assistant.github.io with documentation (if applicable): home-assistant/home-assistant.github.io#<home-assistant.github.io PR number goes here>

Entry for configuration.yaml :

device_tracker:
  - platform: unifi
    username: admin
    password: xxx
    host: 192.168.1.10
    verify_ssl: false
    detection_time: 120
    ssid_filter:
      - 'xxx'
    new-device-defaults:
      track_new_devices: False
      hide_if_away: False

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

[houndci-bot]

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[houndci-bot]

the backslash is redundant between brackets

[homeassistant]

Hi @Zepheus,

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[balloob]

Thanks! 🐬

[Sinbad2000]

Thank you all :)