hot reloading with esbuild only works with WebSerial

[alexrudd2]

Here's my best understanding of the various options and servers involved.

Notice the penultimate row. npm run dev uses esbuild to serve the compiled UI, but there would be no websocket server or NodeSerialPort instnace to actually talk to the EBB.

	UI compiler	CLI compiler	EBB comms	UI server	websockets
npm run deploy, IS_WEB = True	esbuild	N/A	WebSerial	gh-pages	no
npm run start, IS_WEB = True	esbuild + tsconfig-web	N/A	WebSerial	Express	no
npm run start, IS_WEB = False	esbuild + tsconfig-web	esbuild + tsconfig	NodeSerialPort	Express	yes
npm run dev, IS_WEB = True	esbuild + tsconfig-web	N/A	WebSerial	esbuild serve	no
npm run dev, IS_WEB = False	esbuild + tsconfig-web	esbuild + tsconfig	NodeSerialPort	esbuild serve	BROKEN
npm run test	esbuild + tsconfig-web	esbuild + tsconfig	mocked	Express	yes

@jedahan