APY calculation differs from webapp

[varanauskas]

The APY calculation in the webapp has been updated with epoch_period

(Anchor-Protocol/anchor-web-app#353)

https://github.com/Anchor-Protocol/anchor-web-app/blob/d43ab70b8e85dfa144e506160d904d897fcbb27d/app/src/%40anchor-protocol/app-fns/logics/earn/computeApy.ts#L10

This logic is not replicated in earn.getAPY

anchor.js/src/facade/earn/earn.ts

Line 83 in df76c7f

return new Dec(epochState.deposit_rate).mul(BLOCKS_PER_YEAR).toNumber();