fix: removes avoid-contracts in favour of --skip

[dutterbutter]

Dependent on: Moonsong-Labs/compilers#39 and #698
Closes: #670

Question:

• Should we add an alias to --skip for --avoid-contracts to avoid any breaking changes?

What 💻

• Removes --avoid-contracts in favour of --skip

Why ✋

• Make use of the expected foundry behaviour

Evidence 📷

Include screenshots, screen recordings, or console output here demonstrating that your changes work as intended

[Karrq]

During the review I was confused because I couldn't see where we now used skip, but it seems like we already supported it here.
Good stuff, this is definitely something we needed to cleanup :)

[dutterbutter]

@Karrq what you think re:

Should we add an alias to --skip for --avoid-contracts to avoid any breaking changes? I think aave makes use of --avoid-contracts for instance?