Set chiado deprecated slots to zero

[dapplion]

Chiado network deployed for the shapella the contract at commit 13e1555. This contract version was latter replaced with the contract at commit 8fe75d2. The latter version leaves some storage slots orphan, which may cause problems in future updates.

This PR introduces a method to set the gap slots to zero. _deprecated_slots_gap variable is added once to set storage slots 69,70,71 back to zero

SBCDepositContract     │           withdrawableAmount           │      67      │                  t_mapping(t_address,t_uint256)                   │      32       │
SBCDepositContractOld  │ failedWithdrawalIndexByWithdrawalIndex │      68      │                   t_mapping(t_uint64,t_uint256)                   │      32       │
SBCDepositContractOld  │       numberOfFailedWithdrawals        │      69      │                             t_uint256                             │      32       │
SBCDepositContractOld  │          nextWithdrawalIndex           │      70      │                             t_uint64                              │       8       │
SBCDepositContractOld  │        failedWithdrawalsPointer        │      71      │                             t_uint256                             │      32       |

Deployment plan

• Upgrade contract to this implementation
• Call setSlotGapToZero
• Forget about it

---

• Replaces fix: chiado #46 and fix/deprecated slots gap #47

[filoozom]

This script has been ran to its completion and all slots are now zeroed out on Chiado. Can we close this PR @dapplion?

[dapplion]

All slots in chiado have been reset