[KA] Implement new style for keyboard accessory actions.

Keyboard accessory is a chip that isn't backed by an Autofill
suggestion. It's purpose is to perform some action. Credman "select
passkey" action is an example of such an action.

This CL implements styling of the keyboard accessory action chips
and adds corresponding render tests.

Before: screen/5uz62iC4DRsFGrp
After: screen/4HJLiwqnRQ5RqXA

Bug: 385172647
Change-Id: Id8bae34a7d9db6c01fc95ea63af3c693ace018ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6988368
Reviewed-by: Luchen Peng <luchenpeng@google.com>
Commit-Queue: Timofey Chudakov <tchudakov@google.com>
Cr-Commit-Position: refs/heads/main@{#1521338}