Remove redundant AR from example

[timbotimbo]

Description

The example project contains several AR references, even though there is no AR example included.
This causes several issues for people that might not even plan to use AR.

Redundant:

Flutter:

• 'Enable AR' toggle in the Menu that doesn't do anything.

Unity:

• The project includes multiple AR packages using the Unity Package Manager.
  (ARFoundation, ARKit and ARcore and XR plugin management)
  These are not used by any example code.

Issues

The flutter button is confusing as users might expect AR to work in the current example.

The Unity packages cause several issues:

• Switching Unity versions is more likely to cause package resolve conflicts.
• iOS Simulators won't work if the ARfoundation package is installed, even if you don't use it.
• XR Plugin Management version 4.3.1-4.3.3 breaks the android export
  (see [XR Plugin Management] AndroidManifest.xml not found in unityLibrary/AndroidManifest.xml #801)
  Some Unity 2022 versions automatically update the example to these buggy versions.

Anyone smart enough to use ARFoundation, will figure out how to add these packages to their project.
Let's remove these packages from the example to reduce the amount of problems that might pop up.

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore

[k0uhe1D]

LGTM, thank you for always maintaining it!

[k0uhe1D]

Just as an FYI, it is recommended to remove the following packages by default if they are not needed. This is because there is validation for the relevant packages in the internal implementation of URP, and removing them can lead to some performance optimization.

flutter-unity-view-widget/example/unity/DemoApp/Packages/manifest.json

Lines 40 to 42 in ed7a706

	"com.unity.modules.vr": "1.0.0",
	"com.unity.modules.wind": "1.0.0",
	"com.unity.modules.xr": "1.0.0"

[timbotimbo]

@k0uhe1D
Good to know, I'll have to check that out the next time i'm using URP.

Given that those are listed under 'Built-in' instead of 'In Project', i've left those alone for now.
Someone might run into an error and I bet most tutorials don't mention enabling a built-in package.

My main purpose here was to get rid of XR Plugin Management, as I've ran into that bug multiple times when simply upgrading to different Unity versions.