fix: make browser detection more reliable (#768)

Some implementations of server-side rendering support `window` and `document` objects but `navigator` could be undefined. To prevent error-prone behavior we should check the existence of `navigator` object in global scope.

packages/popper/src/utils/isBrowser.js

@@ -1 +1 @@
-export default typeof window !== 'undefined' && typeof document !== 'undefined';
+export default typeof window !== 'undefined' && typeof document !== 'undefined' && typeof navigator !== 'undefined';