*: bn version v2

[KaloyanTanev]

Bump go-eth2-client
Prefer /eth/v2/node/version, falling back to V1 when unsupported and to the eth1 client when V2 omits the execution client. Records each BN's V2-reported EL as its own gauge entry.

category: feature
ticket: none

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
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 68.42105% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.09%. Comparing base (102e83c) to head (67f40d0).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
app/eth2wrap/eth2wrap_gen.go	0.00%	16 Missing ⚠️
app/monitoringapi.go	95.12%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4504      +/-   ##
==========================================
+ Coverage   57.08%   57.09%   +0.01%     
==========================================
  Files         245      245              
  Lines       32886    32923      +37     
==========================================
+ Hits        18774    18799      +25     
- Misses      11742    11753      +11     
- Partials     2370     2371       +1     

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