Log to logstash when VIP Search ratelimiting starts.

[brandon-m-skinner]

Description

We need a way to know if VIP Search is currently rate limited or not on specific sites when debugging. By logging to logstash when rate limiting kicks off and knowing how long rate limiting lasts, it makes debugging much easier since you don't need to guess.

Changelog Description

Log to logstash when VIP Search rate limiting begins

To assist with debugging VIP Search related issues, we need an easy way to determine if rate limiting is currently in effect for queries or indexing operations. The easiest way to accomplish this right now is by logging when rate limiting starts to logstash.

#1916

Checklist

Please make sure the items below have been covered before requesting a review:

• This change works and has been tested locally (or has an appropriate fallback).
• This change works and has been tested on a Go sandbox.
• This change has relevant unit tests (if applicable).
• This change has relevant documentation additions / updates (if applicable).
• (For Automatticians) I've created a changelog draft.

Steps to Test

1. Apply PR.
2. Trigger rate limiting.
3. Check for appropriate logstash-related behaviour.

[brandon-m-skinner]

Need to sort out the failing test. Shouldn't be too difficult.

[brandon-m-skinner]

r1313-stacks