Color changes in default project template prevent flyout button from being visible

[sigged]

Description

In the latest template changes, some styles in the default MAUI project prevent the flyout menu button from being visible.
For example, the Shell.Background color used to be set to Primary, but it is now White. On Android (light theme), this effectively makes the white menu button invisible. This is less than ideal for new devs or students being introduced to MAUI.

I can see that this change was introduced in the following PR, but I'm not really sure why it was needed to change the color to white in the first place.

https://github.com/dotnet/maui/pull/18379/files#diff-dff3632615a2abc5f36f61b4f18f021b08fc73d583ba0453b061815b4ec25b46

To fix this, the style changes should either be reverted or the color of the menu icon should change as well.

Steps to Reproduce

1. Create a new .NET MAUI project
2. In AppShell.xaml, set the following: Shell.FlyoutBehavior="Flyout"
3. Run the project on a device using light theme
4. Try to find the menu button 🔍

Link to public reproduction project repository

No response

Version with bug

8.0.3 GA

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

8.0.0-rc.2.9511

Affected platforms

iOS, Android, Windows, macOS

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

No response

[PureWeen]

Duplicate of #19178