修复了一些问题

Views/Dialogs/MqttDialog.xaml

@@ -68,7 +68,7 @@
             <TextBlock Text="订阅主题"
                        HorizontalAlignment="Left"
                        Style="{StaticResource TextBlockSubTitle}" />
-            <TextBox Text="{Binding Mqtt.SubTopics, UpdateSourceTrigger=PropertyChanged}" />
+            <TextBox Text="{Binding Mqtt.SubTopic, UpdateSourceTrigger=PropertyChanged}" />
             <CheckBox FontSize="16"
                       Content="是否设为默认"
                       Margin="0 30 0 0"

Views/MqttsView.xaml

@@ -126,7 +126,7 @@
                                          VerticalAlignment="Center"
                                          Margin="0,0,8,0"
                                          FontSize="14" />
-                            <TextBlock Text="{Binding SubTopics}" />
+                            <TextBlock Text="{Binding SubTopic}" />
                         </StackPanel>
                         <StackPanel Orientation="Horizontal"
                                     Margin="0,2">