test/ibc: ensure unique token IDs (backport #4154)

[mergify]

Describe your changes

fixes a panic in strategy when a list of generated token IDs is not unique (as seen in https://github.com/anoma/namada/actions/runs/12213873245/job/34074078139)

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 #4154 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 19c8bc3 has failed:

On branch mergify/bp/maint-libs-0.46/pr-4154
Your branch is up to date with 'origin/maint-libs-0.46'.

You are currently cherry-picking commit 19c8bc31a.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both added:      .github/workflows/ci.yml
	both added:      Cargo.lock
	both added:      Cargo.toml
	both added:      crates/ibc/src/lib.rs
	both added:      wasm/Cargo.lock
	both added:      wasm_for_tests/Cargo.lock

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.46%. Comparing base (396adf1) to head (88815de).
Report is 5 commits behind head on maint-libs-0.46.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           maint-libs-0.46    #4178      +/-   ##
===================================================
- Coverage            74.46%   74.46%   -0.01%     
===================================================
  Files                  341      341              
  Lines               107710   107710              
===================================================
- Hits                 80211    80209       -2     
- Misses               27499    27501       +2     

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