[protocol] Update the "OwnableUpgradeable" contract to conform to the latest OpenZeppelin implementation

[PaulRBerg]

In https://github.com/hifi-finance/hifi/commit/4c1b47d8cade20e2b3436cea328efb1165571ff1, we upgraded to v4.5.2 of the @openzeppelin/contracts-upgradeable package. A version which brought a change to the way the initializer modifier works:

• https://unpkg.com/@openzeppelin/contracts-upgradeable@4.3.1/proxy/utils/Initializable.sol
• https://unpkg.com/@openzeppelin/contracts-upgradeable@4.5.2/proxy/utils/Initializable.sol

[PaulRBerg]

Fixed by https://github.com/hifi-finance/hifi/commit/ce70409eb31428dee7c52a6c8f55dc0c6ad443d9 and https://github.com/hifi-finance/hifi/commit/86ccdbba3fb4ab73fde332731a41f955fdfd5f72.