feat: Outstream operator for TrackStatePropMask

[paulgessinger]

I've found this very helpful for some types of debugging.

[codecov]

Codecov Report

Merging #1165 (225d108) into main (f407b53) will decrease coverage by 0.04%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #1165      +/-   ##
==========================================
- Coverage   47.89%   47.84%   -0.05%     
==========================================
  Files         359      360       +1     
  Lines       18504    18523      +19     
  Branches     8730     8737       +7     
==========================================
  Hits         8863     8863              
- Misses       3605     3624      +19     
  Partials     6036     6036              

Impacted Files	Coverage Δ
Core/include/Acts/EventData/TrackStatePropMask.hpp	100.00% <ø> (ø)
Core/src/EventData/TrackStatePropMask.cpp	0.00% <0.00%> (ø)

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