Update rendering of policy edit transactions in Applications

Summary:
Ref T13411. Since circa D19829, transactions have rendered policy changes in a modern way, notably making "Custom Policy" clickable to show the policy rules.

Edit transactions in Applications still use a separate, older approach to render policies. This produces policy renderings which don't use modern quoting rules and don't link in a modern way.

Make Applications use the same rendering code that other transactions (like normal edit/view edits) use.

Test Plan: Edited policies in Applications, saw more useful transactions in the log. Clicked "Custom Policy" in the transaction log and got a useful explanation of the policy.

Maniphest Tasks: T13411

Differential Revision: https://secure.phabricator.com/D20801