feat: don't crash relayer due to flaky RPCs

[kamiyaa]

Description

• instead of crashing relayer if any RPC calls fail during build_mailboxes and build_validator_announces, we just log the error and metric
• relayer will continue running without those chains

Drive-by changes

Related issues

Fixes #4887

Backward compatibility

Are these changes backward compatible? Are there any infrastructure implications, e.g. changes that would prohibit deploying older commits using this infra tooling?

Yes

Testing

Added unittests to test ensure functions run correctly and log errors in metrics

[changeset-bot]

⚠️ No Changeset found

Latest commit: a495762

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.53%. Comparing base (99c91d8) to head (a495762).
Report is 45 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5115   +/-   ##
=======================================
  Coverage   77.53%   77.53%           
=======================================
  Files         103      103           
  Lines        2110     2110           
  Branches      190      190           
=======================================
  Hits         1636     1636           
  Misses        453      453           
  Partials       21       21           

Components	Coverage Δ
core	87.80% <ø> (ø)
hooks	79.39% <ø> (ø)
isms	83.68% <ø> (ø)
token	91.27% <ø> (ø)
middlewares	79.80% <ø> (ø)

[tkporter]

typo nit