Add Vote Extension varying size testnet (backport #888) (#906)

* Add Vote Extension varying size testnet (#888)

This PR modifies the e2e app to allow varying the size of vote extensions to test the effect of VE on the system performance.
Results of tests executed are also reported here.
This work is being done as part of the v0.38.0 QA.

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#### PR checklist

- [ ] Tests written/updated
- [ ] Changelog entry added in `.changelog` (we use [unclog](https://github.com/informalsystems/unclog) to manage our changelog)
- [ ] Updated relevant documentation (`docs/` or `spec/`) and code comments

(cherry picked from commit 028fb5e)

# Conflicts:
#	RELEASES.md

* Fix conflict

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Co-authored-by: Lasaro <[email protected]>

Author: mergify[bot]