Fix EAS folder id length
Fix EAS folder id length

Summary:
Fixes T2458. Note that because we're using MySQL 5.6, the migration happens offline and locks the table. However, since we only have about 20k columns, it shouldn't take too long.

Test Plan: Upgraded a db dump.

Reviewers: kav-ya, emfree

Reviewed By: emfree

Subscribers: spang

Maniphest Tasks: T2458

Differential Revision: https://phab.nylas.com/D1827

nylas/sync-engine,gale320/sync-engine,Eagles2F/sync-engine,gale320/sync-engine,gale320/sync-engine,jobscore/sync-engine,Eagles2F/sync-engine,closeio/nylas,Eagles2F/sync-engine,nylas/sync-engine,ErinCall/sync-engine,Eagles2F/sync-engine,nylas/sync-engine,jobscore/sync-engine,gale320/sync-engine,ErinCall/sync-engine,jobscore/sync-engine,closeio/nylas,closeio/nylas,Eagles2F/sync-engine,gale320/sync-engine,jobscore/sync-engine,ErinCall/sync-engine,closeio/nylas,nylas/sync-engine,ErinCall/sync-engine,ErinCall/sync-engine