Set balance below existential

[faculerena]

Summary

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

Added a check for setting the balance in tests below the existential minimum

Description

Given that accounts with a balance below the existential minimum get reaped, adding a check to prohibit setting balance below seems logical. If this should not be like this, feel free to correct us.

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

[SkymanOne]

Please merge master

[cmichi]

@faculerena Could you merge master into your PR or allow me to resolve the conflicts?

[faculerena]

I think its ok now @cmichi

[cmichi]

@faculerena There are some CI errors, do you see the Details if you click the link?

The cargo fmt issues can be applied automatically by executing cargo +nightly fmt --all locally.

[faculerena]

Clippy issues fixed and fmt ran. I think the Dylint issues are the same as the other two.

[cmichi]

Thank you, @faculerena!