Wrong state diff checks during nested approval calls

[sebastianst]

Nested approval calls seem to run the same state diff checks as the actual task execution. This lead to failing checks during the DGF.setImplementation task executions for Fjord.

It was locally mitigated by removing the task-specific checks and adding code-less address exceptions to the validation script (letting getCodeExceptions() return the SC.getOwners() array). The exceptions were necessary because the SC multisig records all member addresses in a timestamp mapping, and members are mostly EOAs, thus failing the generic code exception checks, that values of state changes that are addresses must contain code.