declare_class
Declares a contract with a snforge_std::declare call and unwraps the result.
This function will skip declaration and just return the ContractClass if the contract is
already declared (the result of snforge_std::declare call is of type
DeclareResult::AlreadyDeclared)
Fully qualified path: openzeppelin_testing::deployment::declare_class
pub fn declare_class(contract_name: ByteArray) -> ContractClass