Remove usage of legacy url API .query

[peternied]

We should switch to .search which is part of the node api, see https://nodejs.org/docs/latest-v14.x/api/url.html which has more details.

Impacted code

security-dashboards-plugin/server/auth/types/basic/routes.ts

Lines 173 to 174 in fc7b8cc

	const requestQuery = request.url.query as ParsedUrlQueryParams;
	if (requestQuery.nextUrl !== undefined) {

[peternied]

[Triage] We should also look into url.path that is used right above this location in the file.

[cliu123]

Removing the label for 2.0.0 as the PR hasn't been ready yet.