fix(install): vendor type-only imports during `deno ci` (#34459)
`deno ci` was using `GraphKind::CodeOnly` when walking the module graph,
because it never sets a type-check mode and so falls through to the
default. `deno install` uses `GraphKind::All`. Files referenced only via
`import type` (e.g. `@std/internal/build_message.ts` importing
`./types.ts`) were therefore skipped during `deno ci` and never written
to the `vendor/` folder, and a subsequent `deno test --cached-only`
would fail with `Specifier not found in cache`.
Fix is a one-line addition to `CliOptions::graph_kind()` so `ci` gets
the same `GraphKind::All` treatment as `install`. The new spec test
uses the existing `@denotest/type-only-import` JSR fixture to guard the
regression.
Closes #34436
