rollup_config.toml is stashed by the sov-celestia-local setup and runs a risk of being committed

[dubbelosix]

Summary

Currently, rollup_config.toml (the default location for demo-rollup config) is modified by the sov-celestia-local setup. Because this is run pretty frequently, it runs a risk of being committed (And as of the time of creating this issue, it has already been committed). This is not necessary and a new rollup config toml file can be generated and used since demo-rollup and demo-prover can both take the config file as an argument. Creating a new file would keep the stash clean and avoid the risk of committing the changes

[citizen-stig]

Might be duplicate of #445