feat: support Aqara Wireless Mini Switch E1 (WXKG20LM)

[hannoeru]

Proposed change

Support Aqara Wireless Mini Switch E1 (WXKG20LM)

Close #1939

Additional information

Reference: https://www.zigbee2mqtt.io/devices/WXKG20LM.html

Device diagnostics

Checklist

• The changes are tested and work correctly
• pre-commit checks pass / the code has been formatted using Black
• Tests have been added to verify that the new code works
• Device diagnostics data has been attached

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.28%. Comparing base (35d1fc1) to head (49fc70e).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #4569   +/-   ##
=======================================
  Coverage   92.28%   92.28%           
=======================================
  Files         371      371           
  Lines       12158    12160    +2     
=======================================
+ Hits        11220    11222    +2     
  Misses        938      938           

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