fix(core-p2p): malformed condition for filtering peers

[vasild]

Currently we would leave in the list all peers that:
"are not me or have invalid port or have invalid version"
the intention must have been:
"are not me and have valid port and have valid version".

This change was first done in 0c23196 and was later reverted in
109a4d3 with a scarce explanation: "it randomly causes issues". It is
not clear what those issues were.

However the current code is strikingly and obviously wrong - it would
add peers that have invalid port, for example.

So, fix the wrong code and followup by fixing any issues that arise, but
not by resurrecting the wrong code.

Proposed changes

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (improve a current implementation without adding a new feature or fixing a bug)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Build (changes that affect the build system)
• Docs (documentation only changes)
• Test (adding missing tests or fixing existing tests)
• Other... Please describe:

Checklist

• I have read the CONTRIBUTING documentation
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[codecov-io]

Codecov Report

Merging #1939 into develop will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff            @@
##           develop    #1939   +/-   ##
========================================
  Coverage    39.24%   39.24%           
========================================
  Files          363      363           
  Lines         7840     7840           
  Branches      1172     1172           
========================================
  Hits          3077     3077           
  Misses        4748     4748           
  Partials        15       15

Impacted Files	Coverage Δ
packages/core-p2p/src/monitor.ts	0% <0%> (ø)	⬆️

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[faustbrian]

This caused issues on testnet and seeds where they would endlessly loop because there were no peers after this change, that is why it was reverted.

[vasild]

So, on testnet all peers in peers.json have invalid port? How do I reproduce that problem?