Remove custom value for max_allowed_request_size_in_bytes

There is no explanation for why this option was bumped to 1 MB instead
of the upstream default. This has been the case since the original
barbican role commit in 2016.

Restore upstream default in Yoga.

Change-Id: Ib0245f44d2b049f7e2254d8d2ea4b2080a8d62dd