[FTS] UI: No warnings in web admin UI about loss of replica indexes after failover

Build
4.5.0-1630

Testcase (to be merged)
./testrunner -i INI_FILE.ini -p skip-cleanup=True,get-cbcollect-info=False,get-logs=False,stop-on-failure=False -t fts.moving_topology_fts.MovingTopFTS.failover_non_master_during_index_building,items=10000,cluster=D,F,F,index_replicas=1,GROUP=P0

Steps
1. To a kv node cluster, add 2 fts nodes, rebalance.
2. Load 10K docs into a bucket
3. Create an index with default mapping with index_replicas=1.
4. Index starts building. After 10 secs, hard failover one of the fts nodes. Rebalance out.
5. Index building continues to 100%.

However there is no warning on UI about the loss of replicas.