DO NOT MERGE IpConnectivityMetrics reads buffer size in settings

Test: IpConnectivityMetricsTest passes. Also manually changed the new
setting and verified the buffer size is as expected after flushing the
buffer.
Bug: 32198637

(cherry pick from commit 05686dbb6b965eb1a54591d2ed2334337886c6ee)

Change-Id: Ie7ca1638533479601c5983bb6e54705003561b6c
3 files changed