webview: Increase non embedded metrics timeout

We are getting data suggesting that the 2 second timeout
for non embedded metric reporting is currently too
aggressive and leading to ~2% of metric logs timing out.

The metrics logs are roughly every five minutes
so we can add plenty more time to this time out.

Bug: 1248039
Change-Id: I952828c66acc848073bcd760eaeb91d7cd4b13c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4325908


Commit-Queue: Richard Coles <torne@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Auto-Submit: Rupert Wiser <bewise@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1115264}