p2p: do not register closing peer

[algorandskiy]

Summary

There was a possible race condition between starting a new wsPeer (that starts reading/writing goroutines), and registering this peer in wsPeers map. wsNetwork.addPeer had such check but p2pNetwork.wsStreamHandler missed it. See failed test logs for demo.

Additionally fixed asserts in catchup tests - on an error they were logging incorrect error object.

Test Plan

Discovered by a test added in #6082

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 56.26%. Comparing base (edda2ee) to head (d7ce2bf).

Files	Patch %	Lines
network/p2pNetwork.go	0.00%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6086      +/-   ##
==========================================
+ Coverage   55.95%   56.26%   +0.31%     
==========================================
  Files         488      488              
  Lines       69602    69606       +4     
==========================================
+ Hits        38945    39164     +219     
+ Misses      27967    27787     -180     
+ Partials     2690     2655      -35     

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