Removes old reference to encrypted txs (backport #3850)

[mergify]

Describe your changes

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 #3850 done by [Mergify](https://mergify.com).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.21%. Comparing base (97b480f) to head (828cd3a).
Report is 3 commits behind head on 0.44.0.

Additional details and impacted files

@@            Coverage Diff             @@
##           0.44.0    #3916      +/-   ##
==========================================
- Coverage   73.22%   73.21%   -0.01%     
==========================================
  Files         341      341              
  Lines      105281   105280       -1     
==========================================
- Hits        77088    77083       -5     
- Misses      28193    28197       +4     

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