Require 2 ACKs from kafka brokers per default

We already required 2 ACKs from kafka brokers for bits, mobile, and
text. Since that did not cause issues, we now require 2 ACKs per
default, and thereby also require 2 ACKs for upload.

Bug: 69667
Change-Id: I72acc4afd3f9699d101db18fa8e0e29ca49ed2ab