R1:9cf26e5e3b10

Improve policy description strings in ApplicationTransactions

Summary: Ref T3184. See discussion in D6042.

Test Plan: {F44265}

Reviewers: garoevans, btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T3184

Differential Revision: https://secure.phabricator.com/D6047