Previously: #72784

Task:

• Remove all traces of the Box component in @wordpress/ui

Background:

See: #72784 (comment)

There was some recent discussion in #73931 (comment) about the value of component abstractions like Box or Text. In reflection, I'm not as convinced to the imminent value of Box as currently implemented. One of the original arguments I raised in #73931 was that this would provide useful guardrails for token usage, but we also recognize that Box is a very low-level abstraction that ideally most people wouldn't need to be using directly anyways. And so if that leaves usage primarily for folks iterating on the design system, those people would already be well-positioned to understand correct usage of the tokens. There are also some trade-offs already acknowledged elsewhere, like mixing and matching different token types (e.g. color and dimensions in Box), excessive DOM element nesting, etc.