Remove testify suite when necessary and reduce test duplication

[julienrbrt]

Summary

We are in the process of improving further our tests (#14145).
The SDK is overly using testify suite, even when the suite only has one test (e.g. #14545).

Moreover, many tests have been duplicated during the creation of e2e tests. We should verify what tests are equivalent and keep only the necessary (this should lead to no coverage decrease)

Work Breakdown

• Remove testify suite when it simplifies a test. The removal should happen package per package.
• Verify test duplication. We have duplicated many tests when using mocks, integration and e2e. Per package, we should ensure we do not duplicate tests.
• Verify the flakiness of the migrated packages with act or directly in CI.

Tasks

Basically, all packages in the Cosmos SDK that have e2e tests should be checked.

• auth
• authz
• bank
• client
• crisis
• distribution
• evidence
• feegrant
• genutil
• gov
• group
• mint
• nft
• params
• server
• slashing
• staking
• tx
• upgrade

[julienrbrt]

Supersede by #20800