[CI] Fix copilot setup steps

[radical]

Prompted by:

/home/runner/work/aspire/aspire/eng/Versions.targets(49,67): error MSB4057: The target "GitInfo" does not exist in the project. [/home/runner/work/aspire/aspire/src/Aspire.AppHost.Sdk/Aspire.RuntimeIdentifier.Tool/Aspire.RuntimeIdentifier.Tool.csproj]

[Copilot]

Pull Request Overview

This PR addresses an issue encountered during the build process where the "GitInfo" target was missing by modifying the CI environment variable setup in the GitHub workflow.

• Added an env block to set CI to false before building the solution.
• Prevents GitInfo errors during the build.

Comments suppressed due to low confidence (1)

.github/workflows/copilot-setup-steps.yml:21

• [nitpick] Setting CI to false in this step helps avoid GitInfo errors, but consider verifying that this change doesn't inadvertently affect other CI-dependent operations. If possible, limit the scope of this override to only the necessary command.

env:

[mitchdenny]

When I ran ./build.sh in codespaces with prepareforhelix true but left CI as default value it worked, so I think this change will work for whatever environment Copilot creates for itself.

[radical]

Validated in https://github.com/dotnet/aspire/actions/runs/15129078539/job/42526461423

[radical]

Merging without waiting for the tests workflow because this change only affects the copilot setup steps.