Add notification dots to thread summary icons (#12146)

* Add notification dots to thread summary icons

Adopts new IndicatorIcon from compound to have threads icons with
indicator dot (that aren't also buttons). Adds green & red dots on
the threads icon in the thread summary to indicate notifications.
Changes the notification level dots colours in the threads panel to
be green to match.

* Update test for new CSS class

* Update snapshots with new class name

* Another snapshot update for new class name

* Replace more uses of old class name in tests

* More snapshot updates for new class name

* Unsure how this ever worked in chronological mode

* More snapshot updates

* Fix dot colours

* Upgrade to compound-web 3

* Fix computed notification levels

* Add test for notificationLevelToIndicator

test/components/views/rooms/NotificationBadge/StatelessNotificationBadge-test.tsx

@@ -25,7 +25,7 @@ describe("StatelessNotificationBadge", () => {
         const { container } = render(
             <StatelessNotificationBadge symbol="!" count={0} level={NotificationLevel.Unsent} />,
         );
-        expect(container.querySelector(".mx_NotificationBadge_highlighted")).not.toBe(null);
+        expect(container.querySelector(".mx_NotificationBadge_level_highlight")).not.toBe(null);
     });
 
     it("has knock style", () => {