Updates forge-std to v1.8.0, restrict state mutability of some functions to avoid compiler warnings.
Note: This is a breaking change, requiring the user's project to use forge-std v1.8.0 or later.
One of the test contracts in this project has a selfdestruct, which we use as part of the upgrade safety validation tests. However, this gives a compiler warning since selfdestruct is deprecated. This PR changes this tescase to use a delegatecall instead.