CmdPal: Add settings to control which fallbacks are enabled (#40505)

This adds settings to each provider to allow us to control if individual
fallback items are enabled or not, regardless of the provider being
enabled.

This is relevant to _all the threads where disabling fallback commands
came up_

This just adds another section to each provider's settings page, with a
list of the fallback commands.

This also has nothing to do with the "top-level apps search", which is
not really a fallback command - it's its own thing.

Ref #38288. Doesn't close that, because this only controls
enable/disable, not ranking.

From here, we should be able to add a dedicated page in the SUI that
shows all the fallbacks across all providers. That's where we'll enable
the ordering.

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/ExtensionPage.xaml

@@ -106,6 +106,40 @@
                                     </ItemsRepeater.ItemTemplate>
                                 </ItemsRepeater>
 
+                                <TextBlock
+                                    x:Uid="ExtensionFallbackCommandsHeader"
+                                    Style="{StaticResource SettingsSectionHeaderTextBlockStyle}"
+                                    Visibility="{x:Bind ViewModel.HasFallbackCommands}" />
+
+                                <ItemsRepeater
+                                    ItemsSource="{x:Bind ViewModel.FallbackCommands, Mode=OneWay}"
+                                    Layout="{StaticResource VerticalStackLayout}"
+                                    Visibility="{x:Bind ViewModel.HasFallbackCommands}">
+                                    <ItemsRepeater.ItemTemplate>
+                                        <DataTemplate x:DataType="viewModels:TopLevelViewModel">
+                                            <controls:SettingsCard DataContext="{x:Bind}" Header="{x:Bind DisplayTitle, Mode=OneWay}">
+                                                <controls:SettingsCard.HeaderIcon>
+                                                    <cpcontrols:ContentIcon>
+                                                        <cpcontrols:ContentIcon.Content>
+                                                            <cpcontrols:IconBox
+                                                                Width="20"
+                                                                Height="20"
+                                                                AutomationProperties.AccessibilityView="Raw"
+                                                                SourceKey="{x:Bind Icon, Mode=OneWay}"
+                                                                SourceRequested="{x:Bind helpers:IconCacheProvider.SourceRequested}" />
+                                                        </cpcontrols:ContentIcon.Content>
+                                                    </cpcontrols:ContentIcon>
+                                                </controls:SettingsCard.HeaderIcon>
+
+                                                <!--  Content goes here  -->
+                                                <ToggleSwitch IsOn="{x:Bind IsEnabled, Mode=TwoWay}" />
+
+
+                                            </controls:SettingsCard>
+                                        </DataTemplate>
+                                    </ItemsRepeater.ItemTemplate>
+                                </ItemsRepeater>
+
                                 <TextBlock
                                     x:Uid="ExtensionSettingsHeader"
                                     Style="{StaticResource SettingsSectionHeaderTextBlockStyle}"

src/modules/cmdpal/Microsoft.CmdPal.UI/Strings/en-us/Resources.resw

@@ -241,6 +241,10 @@ Right-click to remove the key combination, thereby deactivating the shortcut.</v
     <value>Commands</value>
     <comment>A section header for information about the app</comment>
   </data>
+  <data name="ExtensionFallbackCommandsHeader.Text" xml:space="preserve">
+    <value>Fallback commands</value>
+    <comment>A section header for information about the commands presented to the user when the search text doesn't exactly match the name of a command.</comment>
+  </data>
   <data name="ExtensionDisabledHeader.Text" xml:space="preserve">
     <value>This extension is disabled</value>
     <comment>A header to inform the user that an extension is not currently active</comment>