QA Rich Card: add google search link

Add the Google Search link label at the bottom of the rich card views.
This label links to searching the query text in a new tab just as
clicking the original quick answers card did previously.

Screenshots: 
https: //screenshot.googleplex.com/NiMTdCPLu2ehK3b.png
https: //screenshot.googleplex.com/8ZHR4jpsVaSLQFf.png
Bug: b/280500314
Change-Id: If3d85fc06e0cd86e796a99f7f5b2bc006157a876
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4547998


Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Commit-Queue: Angela Xiao <angelaxiao@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1149313}