tabs_api: Rename TabId to NodeId

This change is because the TabId identifier is not only identifying
Tabs, but also collections. This makes the identifier more generic, and
not only tied to Tabs.

Bug: 412935316
Change-Id: I29c013ae2285810b3c78416dd0d616d5936ea030
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6633494
Reviewed-by: Tom Lukaszewicz <tluk@chromium.org>
Reviewed-by: Giovanni Ortuno Urquidi <ortuno@chromium.org>
Commit-Queue: Keren Zhu <kerenzhu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1472528}