p13n: update policy definition

Update the description and caption strings for Sea Pen Wallpaper and VC
background policies.
Also use cr-tooltip-icon for enterprise icon to display tooltip for both
hover and focus mode.

Bug: b/346840273
Test: browser_test --gtest_filter=*GenAI*Policy*
Change-Id: Ic9626730dea8a0e7911b751498d1f2ce143f3713
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5636849


Commit-Queue: Thuong Phan <thuongphan@chromium.org>
Reviewed-by: Sergey Poromov <poromov@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1316540}