p2p: update metrics to support transport comparison

[DiogoSantoss]

Add scrape of libp2p_swarm metrics and transport label to existing libp2p metrics.

category: feature
ticket: #4199

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 3.77358% with 51 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.89%. Comparing base (f3a3df7) to head (ff09a44).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
p2p/metrics.go	0.00%	24 Missing ⚠️
app/app.go	0.00%	23 Missing ⚠️
p2p/p2p.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4239      +/-   ##
==========================================
- Coverage   56.94%   56.89%   -0.05%     
==========================================
  Files         237      237              
  Lines       30824    30886      +62     
==========================================
+ Hits        17554    17574      +20     
- Misses      11033    11077      +44     
+ Partials     2237     2235       -2     

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