test: add tests for v2 transfer vesting account

[gjermundgaraba]

Description

Adds tests for v2 transfer module with vesting accounts.

Needed some more capabilities in the testing suite. Let me know if my approach is alright.

closes: #7658

---

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• Targeted PR against the correct branch (see CONTRIBUTING.md).
• Linked to GitHub issue with discussion and accepted design, OR link to spec that describes this work.
• Code follows the module structure standards and Go style guide.
• Wrote unit and integration tests.
• Updated relevant documentation (docs/).
• Added relevant godoc comments.
• Provide a conventional commit message to follow the repository standards.
• Include a descriptive changelog entry when appropriate. This may be left to the discretion of the PR reviewers. (e.g. chores should be omitted from changelog)
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• Review SonarCloud Report in the comment section below once CI passes.

[AdityaSripal]

Looks good to me, I suppose we should have those testing functions anyway

[DimitrisJim]

changes make sense to me, nice! Function docs need updating/to be added though.

Would also be nice to add these to the changelog since testing is very commonly consumed by people. (That final point though could generally be added when changelog for ibc-eureka changes is done)

[sonarqubecloud]

Quality Gate passed for 'ibc-go'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[DimitrisJim]

Markdown link checker failure is addressed in SDK pr iirc!