Be more specific with required file

[EiNSTeiN-]

This fixes a problem with being unable to load ActionView::Helpers::AssetUrlHelper from L7 in some situations

@rafaelfranca

[rails-bot]

Thanks for the pull request, and welcome! The Rails team is excited to review your changes, and you should hear from @arthurnn (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[arthurnn]

not sure why CI is failing, any clue?

[EiNSTeiN-]

It looks unrelated, unfortunately I can't re-run the ci build (or if I can, I can't find the button to do it)

[rafaelfranca]

I was debugging why this happening. When we require the action_view top file it setup an autoload hook for ActionView::Helpers pointing to action_view/helpers. In @EiNSTeiN- situation seems like a gem is define ActionView::Helpers before sprockets-rails is loaded so action_view/helpers will never be loaded since we only load it when the constant is missing.

Not loading action_view/helpers will not setup the autoload hooks for the helpers inside that file so we will see the LoadError exception.