Wait for FollowRedirect() in tpcd::trial::TopLevelTpcdTrialBrowserTest

Currently `OnReceiveResponse()` is called without waiting for
`FollowRedirect()` and causes unexpected `OnReceiveResponse()` (if the
redirect is not to be followed) or race conditions in
`NavigationURLLoaderImpl`, causing test failures in the CLs for
https://crbug.com/434182226 that strengthen checks in
`NavigationURLLoaderImpl`.

Bug: 434182226
Change-Id: Id35782d48d0eb29fd7db62362d38a1d83dda6b85
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6803591
Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org>
Reviewed-by: Joshua Hood <jdh@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1494813}