fix: bring back zkvm solc resolution from settings

[elfedy]

Motivation

foundry-compilers api refactor brought a regression regarding using zkvm solc when a solc requirement is specified as logic was lost in the new way to do compiler resolution.

Solution

Use dedicated method with zk specific solc resolution for determining how to assign ZkSolcCompiler's solc field.

Pending

This regression highlights the need to address the following in future PRs:

• Have a way to identify if we will use zkvm or vanilla solc through the whole compilation flow (from logging to sending the info in verify and storing it on build_info)
• Have proper integration test to make sure user settings are honored and the correct compiler is being used to compile.

[Jrigada]

Agree moving solc_version to compilers in the future