ld2420: fix energy mode documentation

[andresv]

What does this implement/fix?

LD2420 energy output mode documentation was incorrect. In energy output mode it returns:

presence: bool
distance: u16
energies: [u16; 16]

Also length was wrong in the example. Correct is 23 00 instead of 00 23.

Here can be seen that parser also already expects energies right after distance field: https://github.com/esphome/esphome/blob/dev/esphome/components/ld2420/ld2420.cpp#L351-L354.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

[probot-esphome]

Hey there @descipher, mind taking a look at this pull request as it has been labeled with an integration (ld2420) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (7baf091) 53.71% compared to head (ac5baab) 53.71%.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #6225   +/-   ##
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  Coverage   53.71%   53.71%           
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  Files          50       50           
  Lines        9404     9404           
  Branches     1653     1653           
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  Hits         5051     5051           
  Misses       4055     4055           
  Partials      298      298           

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[descipher]

Thanks for catching the error, I have a PR in to do a workaround at the moment #6168 If you could do review comment there we can get it done faster that way.