I noticed it is not possible to run mixed vc<>bn clients if builder /
mev is enabled as it applies extra flags from other clients in
`vc_extra_params` as the params are applied based on `cl_type` but it
should be done based on `vc_type`.

I tested this using the [following
config](https://gist.github.com/nflaig/949c8b5101127961023d89de9c206b04)
with both `mev_type: mock` and `mev_type: flashbots`.