metrics: remove the Heartbeat distribution

[lhy1024]

What problem does this PR solve?

Issue Number: Close #9003

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.28%. Comparing base (a99abe3) to head (7a23c61).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9010      +/-   ##
==========================================
- Coverage   76.35%   76.28%   -0.07%     
==========================================
  Files         465      465              
  Lines       70536    70495      -41     
==========================================
- Hits        53856    53779      -77     
- Misses      13338    13364      +26     
- Partials     3342     3352      +10     

Flag	Coverage Δ
unittests	76.28% <ø> (-0.07%)	⬇️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nolouch, rleungx

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-01-17 07:22:56.640200467 +0000 UTC m=+276048.095246611: ☑️ agreed by nolouch.
• 2025-01-17 08:08:36.25907399 +0000 UTC m=+278787.714120140: ☑️ agreed by rleungx.