keyboard_layout_monitor_wayland: Mitigate log spam

With this change we set the current group if already not
set and then look for presence of prveious notification of
xkb state/map. This will reduce the noise in the logs, since
we are seeing the compositor sending us the same group again.

Bug: chromium:1291247
Change-Id: If83e5de30e27d36304cbf99d2fe76ea5d0659963
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4192068
Auto-Submit: Salman Malik <salmanmalik@chromium.org>
Reviewed-by: Lambros Lambrou <lambroslambrou@chromium.org>
Commit-Queue: Salman Malik <salmanmalik@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1096422}

remoting/host/linux/keyboard_layout_monitor_wayland.cc

@@ -172,13 +172,13 @@ void KeyboardLayoutMonitorWayland::ProcessModifiersAndNotifyCallbacks(
     return;
   }
 
+  current_group_ = static_cast<xkb_layout_index_t>(group);
+
   if (!xkb_state_) {
     LOG(WARNING) << "Received modifier without keymap?";
     return;
   }
 
-  current_group_ = static_cast<xkb_layout_index_t>(group);
-
   DCHECK(keymap_);
 
   layout_changed_callback_.Run(GenerateProtocolLayoutMessage());