Remove dependency on React Router

[david-crespo]

We use RR in one spot in this repo:

design-system/components/src/ui/empty-message/EmptyMessage.tsx

Lines 10 to 53 in 5ca148e

	import { Link } from 'react-router-dom'
	import { Button, buttonStyle } from '../'
	const buttonStyleProps = { variant: 'ghost', size: 'sm', color: 'secondary' } as const
	type Props = {
	icon?: ReactElement
	title: string
	body?: string
	} & ( // only require buttonTo or onClick if buttonText is present
	| { buttonText: string; buttonTo: string }
	| { buttonText: string; onClick: () => void }
	| { buttonText?: never }
	)
	export function EmptyMessage(props: Props) {
	let button: ReactElement | null = null
	if (props.buttonText && 'buttonTo' in props) {
	button = (
	<Link className={cn('mt-6', buttonStyle(buttonStyleProps))} to={props.buttonTo}>
	{props.buttonText}
	</Link>
	)
	} else if (props.buttonText && 'onClick' in props) {
	button = (
	<Button {...buttonStyleProps} className="mt-6" onClick={props.onClick}>
	{props.buttonText}
	</Button>
	)
	}
	return (
	<div className="m-4 flex max-w-[14rem] flex-col items-center text-center">
	{props.icon && (
	<div className="mb-4 rounded p-1 leading-[0] text-accent bg-accent-secondary">
	{props.icon}
	</div>
	)}
	<h3 className="text-sans-semi-lg">{props.title}</h3>
	{props.body && <p className="mt-1 text-sans-md text-secondary">{props.body}</p>}
	{button}
	</div>
	)
	}

And it's used only once in the entire org:

https://github.com/oxidecomputer/oxide-computer/blob/f59e4282b775b6ee582535cfc4a44b92a035c370/app/routes/events/index.tsx#L122-L126

If we inline that definition in oxide-computer we can delete EmptyMessage here and remove the dep.

[david-crespo]

Reopened by #100 with use-delegated-links.ts. It's only used on the rfd-site, so we can either inline it there or make it take navigate as an arg so the caller can pass it in.