Add min_sdk_version to connectivity targets

All targets need min_sdk_version 30 to be included in the tethering
APEX. They will actually never be used on SDK 30 and are only loaded on
31, but this is necessary to be included in com.android.tethering.

Bug: 171540887
Test: m
Change-Id: I190fd1f3c9fabff057d0a2bd7f45b63a4fe447b3