fix: use header height for Tendermint consensus state storage

[Farhad-Shabani]

Closes: #1080

Along with this PR

• Removed the check and test for stale mock headers as it was not sufficiently general and did not provide meaningful validation.
• Nit: placing unclog of issue 835 under the breaking-changes

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PR author checklist:

• Added changelog entry, using unclog.
• Added tests.
• Linked to GitHub issue.
• Updated code comments and documentation (e.g., docs/).
• Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• Reviewed Files changed in the GitHub PR explorer.
• Manually tested (in case integration/unit/mock tests are absent).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (4428fa9) 66.63% compared to head (ebcc3e8) 66.81%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1081      +/-   ##
==========================================
+ Coverage   66.63%   66.81%   +0.17%     
==========================================
  Files         204      204              
  Lines       20435    20437       +2     
==========================================
+ Hits        13617    13654      +37     
+ Misses       6818     6783      -35     

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[seanchen1991]

One small nit, otherwise looks good to me

[ancazamfir]

lgtm!