feat(cast): add signature identifier to cast run

[joshieDo]

Motivation

cast run is another command which benefits from the signature identifier. I don't think forge test benefits from it, for example.

Solution

before:

after:

While adding, I noticed another issue. Since the external databases (4byte and sam) do not specify the function outputs, we were getting an empty list of output tokens.

after fix:

[mattsse]

nice