Cannot update a plugin that was installed via `.github\copilot\settings.json`

[DLehenbauer]

Describe the bug

When a plugin is automatically installed via the new support for .github\copilot\settings.json, that plugin cannot be upgraded with /plugin upgrade.

Copilot says the installed failed because it is unable to find the marketplace, even though the marketplace and plugin are both browsable with /plugin marketplace browse.

(I suspect that someone just forgot to merge the new project settings.json with the user settings for the '/plugin upgrade' path.)

Affected version

GitHub Copilot CLI 1.0.2.

Steps to reproduce the behavior

1. Add a marketplace and plugin via .github\copilot\settings.json:

{
  "marketplaces": {
    "my-marketplace": {
      "source": { "source": "url", "url": "https://github.com/me/my-marketplace.git" }
    }
  },
  "enabledPlugins": {
    "test-plugin@my-marketplace": true
  }
}

2. Restart copilot.

3. Verify the marketplace was registered:

> /plugin marketplace list

...
Your Marketplaces:

  • my-marketplace
    Source: URL: https://github.com/me/my-marketplace.git

4. Verify the plugin was installed:

> /plugin list

Installed Plugins:

  • test-plugin@my-marketplace v1.0.0

5. Verify the plugin is browsable in the marketplace:

> /plugin marketplace browse my-marketplace

Plugins in "my-marketplace":
  • test-plugin
    A test plugin.

6. Attempt to upgrade plugin

> /plugin update test-plugin@my-marketplace

Failed to update plugin: Marketplace "my-marketplace" not found

Expected behavior

Plugin is successfully upgraded to version 1.0.1.

Additional context

No response