Remove known issue 416196171 from 3.12 release notes

After investigation and troubleshooting, it was determined that
the behavior in question is expected and not a bug. The issue has since
been marked as "Intended Behavior."

For full details, see the analysis at [1].

[1] https://issues.gerritcodereview.com/issues/416196171#comment11

Change-Id: I391343df1ab45a91c8dd4715c1f6cdc6489dc303