add monitor block height metrics

[FineKe]

• Targeted PR against correct branch (see CONTRIBUTING.md)

• [ ] Linked to github-issue with discussion and accepted design OR link to spec that describes this work.

• [ ] Wrote tests

• [ ] Updated relevant documentation (docs/)

• [ ] Added a relevant changelog entry to the Unreleased section in CHANGELOG.md

• [ ] Reviewed Files changed in the github PR explorer

---

For Admin Use:

• Added appropriate labels to PR (ex. wip, ready-for-review, docs)
• Reviewers Assigned
• Squashed all commits, uses message "Merge PR #XYZ: [title]" (coding standards)

[codecov-commenter]

Codecov Report

Merging #3176 (7e98b6e) into dev (2dbe331) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 7e98b6e differs from pull request most recent head b782830. Consider uploading reports for the commit b782830 to get more accurate results

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@@           Coverage Diff           @@
##              dev    #3176   +/-   ##
=======================================
  Coverage   36.55%   36.55%           
=======================================
  Files         443      443           
  Lines       46484    46484           
=======================================
  Hits        16991    16991           
  Misses      28228    28228           
  Partials     1265     1265