feat(`forge script`): ability to control gas multiplier from within script and different gas calculations per chain

### Component

Forge

### Describe the feature you would like

From X:

>What is missing / not working / wrong with Forge scripts in your opinion?

[An issue] I encountered recently is the lack of ability to control gas multipliers from within the script

Some of my scripts interact with multiple chains using createSelectFork, but for some chains (Linea for example) I need different gas calculations and it requires me to write another script and run the two scripts one after the other in a bash script

By https://x.com/adi_milstein/status/1957799095998853216

### Additional context

_No response_