fix: correct storage gap for ProtocolRegistryStorage (#1673)

Storage gaps should add up to 50. As demonstrated by inspecting storage
via `forge`:

```txt
% forge inspect ProtocolRegistryStorage storage

╭--------------------+--------------------------------------------------------------------+------+--------+-------+--------------------------------------------------------------------------------╮
| Name               | Type                                                               | Slot | Offset | Bytes | Contract                                                                       |
+==================================================================================================================================================================================================+
| _semanticVersion   | ShortString                                                        | 0    | 0      | 32    | src/contracts/core/storage/ProtocolRegistryStorage.sol:ProtocolRegistryStorage |
|--------------------+--------------------------------------------------------------------+------+--------+-------+--------------------------------------------------------------------------------|
| _deployments       | struct EnumerableMap.UintToAddressMap                              | 1    | 0      | 96    | src/contracts/core/storage/ProtocolRegistryStorage.sol:ProtocolRegistryStorage |
|--------------------+--------------------------------------------------------------------+------+--------+-------+--------------------------------------------------------------------------------|
| _deploymentConfigs | mapping(address => struct IProtocolRegistryTypes.DeploymentConfig) | 4    | 0      | 32    | src/contracts/core/storage/ProtocolRegistryStorage.sol:ProtocolRegistryStorage |
|--------------------+--------------------------------------------------------------------+------+--------+-------+--------------------------------------------------------------------------------|
| __gap              | uint256[47]                                                        | 5    | 0      | 1504  | src/contracts/core/storage/ProtocolRegistryStorage.sol:ProtocolRegistryStorage |
╰--------------------+--------------------------------------------------------------------+------+--------+-------+--------------------------------------------------------------------------------╯
```

The `__gap` begins at slot `5` -- however, the gap is of size `47`,
which adds up to `52`. Though this is not an issue, it does defy
convention, and can cause confusion later if a developer assumes the gap
needs to be corrected to add up to 50.

---------

Co-authored-by: Nadir Akhtar <9601075+nadir-akhtar@users.noreply.github.com>
Co-authored-by: Yash Patil <40046473+ypatil12@users.noreply.github.com>

Author: nadir-akhtar