Fix/muon bugs

[kosack]

Some small updates for the muon code (that clearly had no tests!) to work with newer Containers. Mainly, this is to use astropy.coordinate.Angle in mcheader.run_array_direction and muon_reco_functions.py, and also fix a typo.

I'll add some unit tests too

[codecov]

Codecov Report

Merging #762 into master will increase coverage by 0.78%.
The diff coverage is 87.5%.

@@            Coverage Diff             @@
##           master     #762      +/-   ##
==========================================
+ Coverage   69.94%   70.72%   +0.78%     
==========================================
  Files         197      198       +1     
  Lines       10659    10669      +10     
==========================================
+ Hits         7455     7546      +91     
+ Misses       3204     3123      -81

Impacted Files	Coverage Δ
ctapipe/image/muon/tests/test_muon_features.py	100% <ø> (ø)
ctapipe/image/muon/tests/test_muon_fitting.py	100% <ø> (ø)
ctapipe/image/muon/tests/test_muon_reco.py	100% <100%> (ø)
ctapipe/io/hessioeventsource.py	95.23% <100%> (ø)	⬆️
ctapipe/image/muon/muon_reco_functions.py	66.96% <66.66%> (+66.96%)	⬆️
ctapipe/coordinates/angular_frames.py	84.45% <0%> (+4.72%)	⬆️

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