Find a way to pass the names of indexes that exist from the server to the client

[cmfcmf]

Follow-up of #85.

docusaurus-search-local/packages/docusaurus-search-local/src/client/theme/SearchBar/index.tsx

Lines 66 to 76 in 55c6ff1

	try {
	const response = await fetch(`${baseUrl}search-index-${tag}.json`);
	if (!response.ok) return EMPTY_INDEX;
	json = await response.json();
	} catch (err) {
	// An index might not actually exist if no pages for it have been indexed.
	// https://github.com/cmfcmf/docusaurus-search-local/issues/85
	// TODO: we should somehow pass the names of indexes that exist to the
	// client at build time instead of catching the error here.
	return EMPTY_INDEX;
	}