fix(BroadcastProcessor): prevent memory leaks by clearing active subscriptions

[jponge]

Refs: #1532

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.44%. Comparing base (3c6b3f4) to head (6a2c6f0).
Report is 35 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #1536   +/-   ##
=========================================
  Coverage     89.43%   89.44%           
+ Complexity     3282     3271   -11     
=========================================
  Files           457      457           
  Lines         13264    13274   +10     
  Branches       1637     1644    +7     
=========================================
+ Hits          11863    11873   +10     
  Misses          788      788           
  Partials        613      613           

Files	Coverage Δ
...operators/multi/processors/BroadcastProcessor.java	90.47% <100.00%> (+0.47%)	⬆️

... and 9 files with indirect coverage changes