Add "consumer connected" attribute to Xiaomi EU plugs

[TheJulianJES]

For zha-quirks, this fixes #2181
Follow-up PR for ZHA to create the binary sensor:

• Add ZHA "consumer connected" binary sensor for Xiaomi EU plugs home-assistant/core#88194

Tested using a Xiaomi MAEU01 plug on v32 and v41 firmware.
#2181 mentions it also works on an MMEU01 plug (so the other Xiaomi EU plug).

[coveralls]

Pull Request Test Coverage Report for Build 4186948529

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 83.698%

---

Totals
Change from base Build 4129468121:	0.0%
Covered Lines:	6844
Relevant Lines:	8177

---

💛 - Coveralls

[javicalle]

LGTM

[myhomeiot]

@TheJulianJES Maybe it's will be good idea to make this sensor as device_class: plug?
PS: Sorry I doesn't mention this before, I just found that HA has this device class :(
PS2: I test it using customize_glob:

  customize_glob:
    "binary_sensor.*_consumer_connected":
      device_class: plug

[TheJulianJES]

Yep, I also just saw that a couple of days ago 😄
If I don't forget, I'll PR that change to HA in the next few days or so

[TheJulianJES]

@myhomeiot

PR'ed:

• Add device class to ZHA Xiaomi plug "consumer connected" sensor home-assistant/core#89476

Btw., you don't need to use customize.yaml. You can change it using the entity editor: