Add test for DBus RuleEnable and fix memory leak

[zappolowski]

This is mainly done to test whether the current pipeline works properly in terms of coverage reporting.

A nice side-effect is, that I could increase the test coverage a bit and fixed a memory leak while doing so.

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.98%. Comparing base (07b68f0) to head (38b794c).
⚠️ Report is 351 commits behind head on master.
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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1328      +/-   ##
==========================================
+ Coverage   65.71%   65.98%   +0.27%     
==========================================
  Files          50       50              
  Lines        8041     8056      +15     
  Branches      925      925              
==========================================
+ Hits         5284     5316      +32     
+ Misses       2757     2740      -17     

Flag	Coverage Δ
unittests	65.98% <100.00%> (+0.27%)	⬆️

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[bynect]

can I merge it ?