Change GTS app menu when there are no tabs

This change follows the new requirements from UX to match the GTS app
menu when there are no tabs (populateTabletEmptyModeMenu) to the GTS app
menu when there are tabs. This change is part of a larger effort to
create "Desktop-like Incognito Windows on Clank".

Before: https://screenshot.googleplex.com/6npvMzKnzhqFo8E

After: https://screenshot.googleplex.com/8BQ7bXrr2qCUVy7

Bug: 443092947
Change-Id: I6b0aadfc51a3e05f53785a13ba988469f236c75c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6918688
Reviewed-by: Shu Yang <shuyng@google.com>
Reviewed-by: Sirisha Kavuluru <skavuluru@google.com>
Commit-Queue: Michael Wu <mklw@google.com>
Cr-Commit-Position: refs/heads/main@{#1512584}