Revert "AOSP/Email - Bumped the targetSdkVersion to 28 (maximum version) in UnifiedEmail using JobIntentservice."

This reverts commit 44d8e528b5e23a4b7f89f06c8d12d8c7e3678b3b.

Reason for revert: b/124915301

Change-Id: Iac4e70a16d0f1645ec60e54ef68a98f979a14509
6 files changed