Update DApp and Analytics when upgrading Vault for OUSD #1368
Description
The OETH PR #1271 renames the functions priceUSDMint and priceUSDRedeem to priceUnitMint and priceUnitRedeem respectively. But since we haven't upgraded the OUSD Vault yet, we have to be mindful to update the code of DApp and Analytics to use the renamed functions when we finally get to upgrade OUSD Vault.
Doing this will make sure that we don't accidentally break DApp or the Analytics part when the upgrade happens.