Clarify Tasks listed on Project Profiles

Summary: Fixes T6772. Adds additional checks and language. Happy to tweak language.

Test Plan: Test a Project with 3, 10, and 11 tasks.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6772

Differential Revision: https://secure.phabricator.com/D11192