[E2E] Remove additional_contracts parameter

[SkymanOne]

Summary

Closes #_

• y/n | Does it introduce breaking changes?
• y/n | Is it dependant on the specific version of cargo-contract or pallet-contracts?

Description

Removed additiona_contracts parameters from ink_e2e::test macro as this info is implied from the contract's manifest

Checklist before requesting a review

• My code follows the style guidelines of this project
• I have added an entry to CHANGELOG.md
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules

[ascjones]

LGTM!

[cmichi]

Thanks! Please also check the 5.x docs.