Use full utf8mb4 collation names

Summary:
This fixes the following comments:

• Database collate uca1400_as_ci != utf8mb4_uca1400_as_ci needs to be updated
• Database collate utf8_bin != utf8mb4_bin needs to be updated

Test Plan: Deploy on db-B-001

Reviewers: dereckson

Differential Revision: https://devcentral.nasqueron.org/D3070