fix: support npm: specifiers in --preload and --import (#34346)
`deno run --preload npm:foo` and `deno run --import npm:foo` previously
failed with `Could not find constraint 'foo' in the list of packages`,
because the npm package referenced by the preload/import flag was never
installed before the preload module list was resolved. Bare specifiers
that mapped to an npm package via an import map or `package.json`
dependency were also unresolved, since the preload pipeline did not run
them through the workspace resolver.
This change threads the `WorkspaceMainModuleResolver` into
`preload_modules_with_resolver` so bare specifiers in `--import` /
`--preload` resolve the same way as the main module. It also moves npm
package collection inside `CliMainWorkerFactory::create_custom_worker`
to gather requirements from the main module, preload list, and require
list together, and installs them in one batch before resolution
proceeds.
Spec test coverage is added in `tests/specs/run/preload_modules_npm`
exercising both `--import npm:` and `--preload npm:`.
Fixes #34303
