feat(forge): More general `MultiContractRunnerBuilder`

### Component

Forge

### Describe the feature you would like

Tracked by #9012, `MultiContractRunnerBuilder` currently requires the entire output from `foundry_compilers` as input, however it only ever uses a single field on that type.

The problem with this is library users may be constructing their artifacts by different means and do not want to construct the full type.

I propose changing the input to just take in an `ArtifactsContracts<_>`

### Additional context

_No response_

Start by locating MultiContractRunnerBuilder in the Forge code and inspect how it currently consumes foundry_compilers output. Trace the ArtifactsContracts type and the existing builder call sites, then update the input boundary so it accepts ArtifactsContracts directly. Done means callers no longer need to construct the full compiler output type.

Written by the indexing model from the issue text.