[ci] Is dart format doing what we want (in CI)?

While working on an unrelated task, I noticed the following output in the dart format check:

```
Running Dart format...
Warning: Package resolution error when reading "analysis_options.yaml" file for "samples/client/flutter/restaurant_finder/app/lib/main.dart":
Failed to resolve package URI "package:lints/recommended.yaml" in include at "/home/runner/work/a2ui/a2ui/analysis_options.yaml".
Warning: Package resolution error when reading "analysis_options.yaml" file for "samples/client/flutter/restaurant_finder/app/lib/src/main.dart":
Failed to resolve package URI "package:lints/recommended.yaml" in include at "/home/runner/work/a2ui/a2ui/analysis_options.yaml".
Warning: Package resolution error when reading "analysis_options.yaml" file for "samples/client/flutter/restaurant_finder/app/test/widget_test.dart":
Failed to resolve package URI "package:lints/recommended.yaml" in include at "/home/runner/work/a2ui/a2ui/analysis_options.yaml".
Warning: Package resolution error when reading "analysis_options.yaml" file for "samples/client/flutter/restaurant_finder/e2e_test/test/infra_test.dart":
Failed to resolve package URI "package:lints/recommended.yaml" in include at "/home/runner/work/a2ui/a2ui/analysis_options.yaml".
Warning: Package resolution error when reading "analysis_options.yaml" file for "samples/client/flutter/restaurant_finder/e2e_test/test/test_infra/ai_client.dart":
Failed to resolve package URI "package:lints/recommended.yaml" in include at "/home/runner/work/a2ui/a2ui/analysis_options.yaml".
Formatted 13 files (0 changed) in 0.02 seconds.
```

> **Failed to resolve package URI `"package:lints/recommended.yaml"` in include at `".../analysis_options.yaml"`.**

See [this build task](https://github.com/a2ui-project/a2ui/actions/runs/33453710575/job/99689136987?pr=1935#step:7:51).

Are we applying the lints that we expect?

Look at the CI workflow that runs dart format, likely in .github/workflows/. Examine the analysis_options.yaml file at the repository root to see the include for package:lints/recommended.yaml. Check if the lints package is properly resolved in the CI environment, possibly by ensuring dependencies are fetched before formatting. Verify the formatting step still applies the intended lint rules.

索引モデルが issue の本文から書いたものです。