[hooks_runner] Support dependency overrides in `package_graph.json`

[dcharkes]

Currently, we skip running hooks if they are only in the dependency graph with direct dependencies (or dev deps of the root package if we're running tests).

However, one might have a package in the workspace, that is only added as a dependency override somewhere. That currently means it's not visible in the package_graph.json, and we'd skip running the hooks, so the assets wouldn't be bundled. See:

• Flutter 3.35 no longer bundles assets from overridden packages flutter/flutter#174593

Once the package_graph.json has the required info, we should use it.

Workaround: add the package as a normal dependency as well.