node: clear new p2p net handlers on fast catchup

[algorandskiy]

Summary

1. Fast catchup testing showed node did not clear p2p net handlers on fast catchup. Fixed.
2. Renamed ClearProcessors -> ClearValidatorHandlers to have consistent naming with RegisterValidatorHandlers
3. As a followup to a streaming HTTP server workaround p2p: make sure p2p http server runs on all interfaces #6123 - change aux listening on localhost only.

Test Plan

1. Added a new unit test to exercise SetCatchpointCatchupMode

[codecov]

Codecov Report

Attention: Patch coverage is 30.00000% with 7 lines in your changes missing coverage. Please review.

Project coverage is 56.22%. Comparing base (3b3b5ce) to head (475261a).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
network/hybridNetwork.go	0.00%	3 Missing ⚠️
network/p2p/http.go	0.00%	2 Missing ⚠️
network/p2pNetwork.go	0.00%	1 Missing ⚠️
network/wsNetwork.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6127      +/-   ##
==========================================
+ Coverage   54.28%   56.22%   +1.93%     
==========================================
  Files         494      494              
  Lines       69936    69932       -4     
==========================================
+ Hits        37968    39320    +1352     
+ Misses      29246    27932    -1314     
+ Partials     2722     2680      -42     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.