feat: make codebase compatible with v0.8 ref implementation

[Mberic]

1. Changed ERC-4337 rev to the one for v0.8 (i.e., 4cbc060)
2. Changed OpenZeppelin rev from v4.9.3 to v5.5.0 (fcbae53). The previous OpenZeppelin revision (4.9.3) didn't include ReentrancyGuardTransient.sol, which was required for v0.8 of the ERC4337 ref implementation.
3. Main changes in src/ERC4337Checker.sol and test/ files are (1) UserOperation to PackedUserOperation and (2) EntryPoint to EntryPointSimulations. This is because v0.8 separated the simulation logic from the EntryPoint contract. You may verify with the v0.7 changelog
4. The BaseAccount in v0.8 also added the execute function, there4 affecting the MockAccount subclass. So I had to rename the execute defined in MockAccount to executeAttack