Deprecate autolink functionality to copy flags from react-native.config.js into ExperimentalFeature.props.

[jonthysell]

Problem Description

There is a ensureXAMLDialect() function in autolinkWindows.ts that allowed devs to configure their old architecture project to specify useWinUI3 in their react-native config file and let it overwrite the value set in ExperimentalFeatures.props.

This feature is confusing and unnecessary, as we no longer support using WinUI3 in Old architecture projects, nor is it optional in New Architecture projects.

Furthermore, the autolink tests for this feature fail because it was broken with the removal of allowing users to set the WinUI3 value for new Old Architecture projects.

Steps To Reproduce

1. Open packages/@react-native-windows/cli
2. Run yarn test autolink

Expected Results

No response

CLI version

15.0.0-alpha.2

Environment

info Fetching system and libraries information...
System:
  OS: Windows 11 10.0.26400
  CPU: (20) x64 13th Gen Intel(R) Core(TM) i7-13800H
  Memory: 16.00 GB / 31.83 GB
Binaries:
  Node:
    version: 18.18.0
    path: C:\Program Files\nodejs\node.EXE
  Yarn:
    version: 1.22.22
    path: C:\Program Files (x86)\Yarn\bin\yarn.CMD
  npm:
    version: 9.8.1
    path: C:\Program Files\nodejs\npm.CMD
  Watchman: Not Found
SDKs:
  Android SDK: Not Found
  Windows SDK:
    AllowDevelopmentWithoutDevLicense: Enabled
    AllowAllTrustedApps: Enabled
    Versions:
      - 10.0.19041.0
      - 10.0.22000.0
      - 10.0.22621.0
IDEs:
  Android Studio: Not Found
  Visual Studio:
    - 17.13.35931.197 (Visual Studio Enterprise 2022)
Languages:
  Java: Not Found
  Ruby: Not Found
npmPackages:
  "@react-native-community/cli": Not Found
  react: Not Found
  react-native: Not Found
  react-native-windows: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

Community Modules

No response

Target Platform Version

None

Target Device(s)

No response

Visual Studio Version

None

Build Configuration

None

Snack, code example, screenshot, or link to a repository

No response

[sourabratabose]

I am eager to contribute to the project by solving this issue. Would you kindly assign me this issue?