feat!: support static gas price setting in `NodeConfig`

[MujkicA]

Originally, this PR was aiming to solve several bugs and enables a static gas price in our tests so that we can catch said bugs. It was split into several smaller PRs:

1423, #1425, #1426

In it's current version, it only adds the static gas price config parameter to the node config and enables it in our tests.

BREAKING CHANGE: Adds the field static_gas_price to NodeConfig

Checklist

• [ ] I have linked to any relevant issues.
• [ ] I have updated the documentation.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] I have added necessary labels.
• [ ] I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• [ ] I have requested a review from the relevant team or maintainers.

[hal3e]

can you please add the BREAKING CHANGE section in the PR description.