"user.notice aftd-trio: [Notice] Em: FRR: 0 Selector(s) flushed, ActiveNode: 2002219" logs are flooded even in steady/no issue state

Flooding logs are seen during FRR (Fast Re-Route) events triggered by link-down events. This is a cosmetic/non-impacting log. This issue applies to Junos and Evo product-groups.

The log has been reclassified as a debug log as it is non-impacting and fixed in 20.4R2 and later versions via PR1587298.

The Workaround to address this problem is: 
1. These messages are cosmetic, so it is recommended to filter them. Follow the below link to filter these logs: 
https://supportportal.juniper.net/s/article/EX-How-to-filter-two-or-more-specific-messages-from-being-written-to-the-syslog-file

2. Avoid ECMP, MPLS link-protection and LAG configuration on DUT

Initial version