Check author when showing scope notes and votes

[arfon]

This pull request introduces a new method to the Paper model to check if a given user is the submitting author and updates the UI to restrict editors from seeing certain sections for their own submissions. It also adds tests to ensure the new method works as expected.

Model changes:

• Added the submitted_by?(user) method to the Paper model to determine if a given user is the submitting author.

UI changes:

• Updated the unpublished paper view (_show_unpublished.html.erb) so that editors do not see the "vote summary" and "notes" sections for papers they themselves submitted.

Testing:

• Added tests for the submitted_by? method in paper_spec.rb to verify correct behavior for the submitting author, other users, and nil cases.

Fixes #1550

[sneakers-the-rat]

Yep this hides the panels on the deployed preview!