Stop dumping stack in Tab Search for empty URL and update nav doc

Bug: 329638230, 332771304
Change-Id: Idbc1f51d2623eacc7c663bcd565329418528b7a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5425954


Commit-Queue: Keren Zhu <kerenzhu@chromium.org>
Reviewed-by: Thomas Lukaszewicz <tluk@chromium.org>
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1283905}