[Extensions] Retry worker registration timeout errors.

Before this change worker registration would sometimes fail with
blink::ServiceWorkerStatusCode::kErrorTimeout.

We've been advised by the
blink-worker team that this could be a transient error that could be
retried for success.

After this change we now retry registration up to 3 times after each
completion of the registration request to see if this will help reduce
these errors.

This also introduces a metric to track success/failure of the retries
and increments existing registration metrics because they might change
due to the retries that could cause DidRegisterServcieWorker() to be
called multiple times.

OBSOLETE_HISTOGRAMS=Metric incremented since registration retry attempts will change how often they are emitted.

Low-Coverage-Reason: HARD_TO_TEST registration timeout failures are not currently reproducible.
Bug: 346732739
Change-Id: I8a0428ebff0096988c3a9f2a46fff4a7482ffbd9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5767440
Reviewed-by: Devlin Cronin <rdevlin.cronin@chromium.org>
Commit-Queue: Justin Lulejian <jlulejian@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1339103}