Updated password reset process not to indicate if email exists

- Intended to prevent enumeration to check if a user exists.
- Updated messages on both the reqest-reset and set-password elements.
- Also updated notification auto-hide to be dynamic based upon the
amount of words within the notification.
- Added tests to cover.

For #2016

resources/js/components/notification.js

@@ -28,7 +28,11 @@ class Notification {
             this.elem.classList.add('showing');
         }, 1);
 
-        if (this.autohide) setTimeout(this.hide.bind(this), 2000);
+        if (this.autohide) {
+            const words = textToShow.split(' ').length;
+            const timeToShow = Math.max(2000, 1000 + (250 * words));
+            setTimeout(this.hide.bind(this), timeToShow);
+        }
     }
 
     hide() {