miioprotocol: wrap unexpected responses in DeviceException

[rytilahti]

To avoid leaking raw exceptions to downstreams, send() now raises PayloadDecodeException when the device response cannot be decrypted (payload is not a dict), and wraps any other unexpected exception in DeviceException.

Fixes #1913

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 84.16%. Comparing base (2817647) to head (3a7e326).

Files with missing lines	Patch %	Lines
miio/miioprotocol.py	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2081      +/-   ##
==========================================
+ Coverage   84.13%   84.16%   +0.03%     
==========================================
  Files         199      199              
  Lines       20164    20170       +6     
  Branches     1063     1064       +1     
==========================================
+ Hits        16964    16976      +12     
+ Misses       3010     3002       -8     
- Partials      190      192       +2     

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