fix: properly implement requestUpdateAndWait() (#1218)

## Summary

Properly implement `requestUpdateAndWait()` using freeRTOS direct task
notification.

FWIW, I think most of the current use cases of `requestUpdateAndWait()`
are redundant, better to be replaced by `requestUpdate(true)`. But just
keeping them in case we can find a proper use case for it in the future.

---

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src/activities/Activity.cpp

@@ -8,11 +8,7 @@ void Activity::onExit() { LOG_DBG("ACT", "Exiting activity: %s", name.c_str());
 
 void Activity::requestUpdate(bool immediate) { activityManager.requestUpdate(immediate); }
 
-void Activity::requestUpdateAndWait() {
-  // FIXME @ngxson : properly implement this using freeRTOS notification
-  activityManager.requestUpdate(true);
-  delay(100);
-}
+void Activity::requestUpdateAndWait() { activityManager.requestUpdateAndWait(); }
 
 void Activity::onGoHome() { activityManager.goHome(); }