Update feedback form URLs and parameters for todo items

This change splits the feedback form into two separate forms: one for
first-party todo items and another for third-party (tab) todo items. It
also consolidates the various item details (such as heading,
description, score, URL, or group type) into a single slash-separated
details parameter sent to the form so users don't have to scroll so far.

Bug: b:540562062
Change-Id: I239052287eda50fe4808b93c37c8d3d209b62f9a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8302976
Commit-Queue: Sophie Chang <sophiechang@chromium.org>
Auto-Submit: Isabelle Goralsky <igoralsky@google.com>
Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Commit-Queue: Isabelle Goralsky <igoralsky@google.com>
Cr-Commit-Position: refs/heads/main@{#1687518}