Add and modify a few ANA stats.

This CL adds seperate counters for ANA frame length increases and decreases, which gives more insight into what actions are taken. In addition, a new stat is added to track the sum of the uplink packet loss fraction that is set by the ANA FEC controller.


Cr-Original-Commit-Position: refs/heads/master@{#19756}
Cr-Mirrored-Commit: 0d0b9121282c3f63aaaa242779122f5b0c5db96c
7 files changed