Make CI check format of UI tests (#534)

* [ci] Check format of UI tests as well

* [lang] Apply our formatting guidelines to UI tests

* [ci] Make Gitlab happy

* [ci] Remove superfluous space

* [ci] Output rustfmt version

* [ci] Tune rustfmt params

* Remove todo's

* Migrate erc721 ui test contract to recent example contract

* Remove --version command used to debug

* Apply cargo fmt

* .gitlab-ci.yml formatting

* Add main fn

* Remove todo from stderr expect

* Adapt fixtures

* Revert "Adapt fixtures"

This reverts commit 174c012e.

* Adapt fixtures
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