Update approval rules UX when disabled self approval

Description

When "allow self approval" is off for a project, it removes the author from the approval rules. This can be confusing if I'm in a rule by myself (imagine a small open source project) because now it's automatically approved and it shows "None" for approvers.

See "Backend" rule of this screenshot:

Screen_Shot_2019-04-05_at_11.02.39_AM

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