Default to 'off' when invoked on an obviously SSH shell

[cottsay]

While this doesn't determine if invoked over an SSH shell with 100% certainty (like if sudo is involved), it's a trivial hint that the user probably doesn't want desktop notifications enabled.

Note that the behavior can still be specified either way, we're just changing the default behavior here.

Inspired by: #31 (comment)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 19.21%. Comparing base (e535828) to head (b80367b).
⚠️ Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
...ion/event_handler/desktop_notification/__init__.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #76      +/-   ##
==========================================
- Coverage   19.25%   19.21%   -0.05%     
==========================================
  Files           9        9              
  Lines         431      432       +1     
  Branches       65       66       +1     
==========================================
  Hits           83       83              
- Misses        335      336       +1     
  Partials       13       13              

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[Crola1702]

LGTM