Clean IBC E2E tests

[yito88]

Describe your changes

closes #3601

• Also refined the IBC client upgrade test with Gaia

Checklist before merging

• If this PR has some consensus breaking changes, I added the corresponding breaking:: labels
  • This will require 2 reviewers to approve the changes

[yito88]

The new ibc_upgrade_client test requires Gaia v18 or later: heliaxdev/namada-ci#4

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.01%. Comparing base (cc0a448) to head (fc002e5).
Report is 29 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3693      +/-   ##
==========================================
- Coverage   68.01%   68.01%   -0.01%     
==========================================
  Files         330      330              
  Lines      116209   116208       -1     
==========================================
- Hits        79041    79040       -1     
  Misses      37168    37168              

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[sug0]

oh, the upgrade client ibc e2e test failed

[yito88]

oh, the upgrade client ibc e2e test failed

That's expected. It needs a new gaia in CI. heliaxdev/namada-ci#4