Update the strings for the profile switch bubble for supervised users

This applies when the supervised user signs in as a secondary account in one profile, and are already signed in to another profile.

See screenshots in crbug.com/370938618#comment5.

Bug: 370938618
Change-Id: I7799b8b60aa2973dbb9e65f3bbca0b7203af406e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5926049
Reviewed-by: Nicolas Dossou-Gbété <dgn@chromium.org>
Auto-Submit: James Lee <ljjlee@google.com>
Commit-Queue: James Lee <ljjlee@google.com>
Reviewed-by: Ryan Sultanem <rsult@google.com>
Cr-Commit-Position: refs/heads/main@{#1368314}