Modify encoder handler to not call "on_encoder" functions if no change (#1749)

firmware/application/apps/ui_scanner.cpp

@@ -275,7 +275,7 @@ ScannerView::~ScannerView() {
 }
 
 void ScannerView::show_max_index() {  // show total number of freqs to scan
-    field_current_index.set_text("---");
+    field_current_index.set_text("<->");
 
     if (entries.size() == FREQMAN_MAX_PER_FILE) {
         text_max_index.set_style(&Styles::red);

firmware/application/event_m0.cpp

@@ -410,6 +410,9 @@ void EventDispatcher::handle_encoder() {
 
     const uint32_t encoder_now = get_encoder_position();
     const int32_t delta = static_cast<int32_t>(encoder_now - encoder_last);
+    if (delta == 0)
+        return;
+
     encoder_last = encoder_now;
     const auto event = static_cast<ui::EncoderEvent>(delta);
     event_bubble_encoder(event);