[Tech Debt]: interface all data arrays

[emilydrakesmith]

What is needed?

A common code pattern in React is to code an array of curly-brace objects within a React functional component and map over that data to create child elements to render in the DOM. This can cause surprise TS linting issues when one data type is mixed (eg, can be either type JSX.element or string). All data arrays in the app, even if they are only used locally, should have a shape explicitly described by an interface. Example below from the TransactionDetailsSimplify.tsx file: