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.

---

### AI Usage

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Did you use AI tools to help write this code? **YES**, it's trivial, so
I asked an AI to write the code

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/activities/network/WifiSelectionActivity.cpp

@@ -201,6 +201,7 @@ void WifiSelectionActivity::selectNetwork(const int index) {
             state = WifiSelectionState::NETWORK_LIST;
           } else {
             enteredPassword = std::get<KeyboardResult>(result.data).text;
+            // state will be updated in next loop iteration
           }
         });
   } else {
@@ -465,7 +466,6 @@ void WifiSelectionActivity::render(RenderLock&&) {
   // Don't render if we're in PASSWORD_ENTRY state - we're just transitioning
   // from the keyboard subactivity back to the main activity
   if (state == WifiSelectionState::PASSWORD_ENTRY) {
-    requestUpdateAndWait();
     return;
   }