feat(Explore): make sure Loki labels are up to date (#16131)

* Migrated loki syntax and labels logic to useLokiSyntax hook

* Enable loki labels  refresh after specified interval has passed

* Enable periodic loki labels refresh when labels selector is opened

* Fix prettier

* Add react-hooks-testing-library and disable lib check on typecheck

* Add tests for loki syntax/label hooks

* Move tsc's skipLibCheck option to tsconfig for webpack to pick it up

* Set log labels refresh marker variable when log labels fetch start

* Fix prettier issues

* Fix type on activeOption in useLokiLabel hook

* Typo fixes and types in useLokiSyntax hook test fixes

* Make sure effect's setState is not performed on unmounted component

* Extract logic for checking if is component mounted to a separate hook

public/app/core/hooks/useRefMounted.ts

@@ -0,0 +1,12 @@
+import { useRef, useEffect } from 'react';
+
+export const useRefMounted = () => {
+  const refMounted = useRef(false);
+  useEffect(() => {
+    refMounted.current = true;
+    return () => {
+      refMounted.current = false;
+    };
+  });
+  return refMounted;
+};