[Tech Enhancement] Implement standard sizes on `Button` component

### Verified issue does not already exist?

- [X] I have searched and found no existing issue
- [X] I will be providing steps how to reproduce the bug (in most cases this will also mean uploading a demo budget file)

### What happened?

Currently, there is no standard button sizes across the app. This enhancement is to extend the `Button2` component to have a `size` prop which accepts some standard size values:

- small
- medium
- large
- extra-large

These standard sizes should vary between screen sizes e.g. different set of width and height for desktop, tablet, mobile

This change should help make all the buttons more uniform in sizes throughout the app

### Where are you hosting Actual?

None

### What browsers are you seeing the problem on?

_No response_

### Operating System

None

Start by locating the TypeScript definition and usages of the Button2 component, then review how buttons currently size themselves across desktop, tablet, and mobile layouts. Done means Button2 accepts small, medium, large, and extra-large size values and the resulting buttons use consistent responsive width and height throughout the app.

Scritto dal modello di indicizzazione a partire dal testo della issue.