Solr admin UI rapidly retries any request(s) if it loses connection with the server

It seems that whenever the Solr admin UI loses connection with the server, be the reason that the server is too slow to answer or that it's gone away completely, it starts hammering the server with the previous request until it gets a success response, it seems. That can be especially bad if the last attempted action was something like collection reload with a SolrCloud instance. The admin UI will quickly add hundreds of reload commands to overseer/collection-queue-work, which may essentially cause the replicas to get overloaded when they're trying to handle all the reload commands.

I believe the UI should never retry the previous command blindly when the connection is lost, but instead just ping the server until it responds again.

Steps to reproduce:
1.) Fire up Solr
2.) Open the admin UI in browser
3.) Open a web console in the browser to see the requests it sends
4.) Stop solr
5.) Try an action in the admin UI
6.) Observe the web console in browser quickly fill up with repeats of the originally attempted request