configure_hotkeys: Change critical error dialog into a warning dialog

critical() is intended for critical/fatal errors that threaten the
overall stability of an application. A user entering a conflicting key
sequence is neither of those.

src/yuzu/configuration/configure_hotkeys.cpp

@@ -67,7 +67,7 @@ void ConfigureHotkeys::Configure(QModelIndex index) {
     }
 
     if (IsUsedKey(key_sequence) && key_sequence != QKeySequence(previous_key.toString())) {
-        QMessageBox::critical(this, tr("Error in inputted key"),
+        QMessageBox::warning(this, tr("Error in inputted key"),
                              tr("You're using a key that's already bound."));
     } else {
         model->setData(index, key_sequence.toString(QKeySequence::NativeText));