Remove circular dependencies part 2

[artlowel]

References

• Fixes an issue introduced in User agreement #862 the same way Remove circular dependencies #850 did

Description

#862 added new circular dependencies. This PR removes them, and adds a line to the PR template checklist to verify that a new PR isn't introducing new circular dependencies.

As in #850, I didn't add any new code, just moved a few functions and variables to a different file.

Instructions for Reviewers

You can test this PR by verifying that it doesn't break anything involving the user agreement or privacy statement page.

Checklist

• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes TSLint validation using yarn run lint
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• If my PR includes new, third-party dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.

[tdonohue]

👍 Code looks correct & tested it and found the circular dependency warning is fixed. Thanks also for updating our PR template to include this reminder. Thanks @artlowel !