input: Fix hyprctl switchxkblayout not actually changing layout (#7070)

Emits `SModifiersEvent` in `updateModifiers()`

Before the patch:

Changing layout with `hyprctl switchxkblayout ...` results in:
    * active keymap in `hyprctl devices` is changed
    * no event
    * no layout is actually changed UNTIL you press one of the mod keys
      (Alt | Shift | Super | Ctrl)

After:
    * active keymap in `hyprctl devices` changed
    * activelayout IPC event emitted
    * layout is changed

This fixes https://github.com/hyprwm/Hyprland/issues/7044

src/devices/IKeyboard.cpp

@@ -325,6 +325,13 @@ void IKeyboard::updateModifiers(uint32_t depressed, uint32_t latched, uint32_t l
     if (!updateModifiersState())
         return;
 
+    keyboardEvents.modifiers.emit(SModifiersEvent{
+        .depressed = modifiersState.depressed,
+        .latched   = modifiersState.latched,
+        .locked    = modifiersState.locked,
+        .group     = modifiersState.group,
+    });
+
     updateLEDs();
 }