test/e2e: try to clean-up gaiad (backport #3907)

[mergify]

Describe your changes

follow-up to #3894 to forward a Ctrl+C signal to the cmd inner session

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
• If this PR requires changes to the docs or specs, a corresponding PR is opened in the namada-docs repo
  • Relevant PR if applies:
• If this PR affects services such as namada-indexer or namada-masp-indexer, a corresponding PR is opened in that repo
  • Relevant PR if applies:

---

This is an automatic backport of pull request #3907 done by [Mergify](https://mergify.com).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.25%. Comparing base (ea7e418) to head (d677fd1).

Additional details and impacted files

@@            Coverage Diff             @@
##           0.44.0    #3908      +/-   ##
==========================================
- Coverage   73.25%   73.25%   -0.01%     
==========================================
  Files         341      341              
  Lines      105241   105241              
==========================================
- Hits        77096    77095       -1     
- Misses      28145    28146       +1     

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