WebUI: Remove paper- colors from cr_elements

Polymer's paper-styles/color.js was still being used in 3 places in
cr-elements. Remove these imports and replace the colors as follows:
- action_link.css - use fallback color for disabled foreground text,
  which includes an opacity, instead of custom color + opacity.
- profile avatar selector - use equivalent --google- color.
- cr_shared_vars.css - change cr-menu-shadow to default to the 2023
  refresh value for cr-action-menu, since everywhere else that wants
  something different will override it.

Removing the paper colors import from cr_shared_vars can result in
this file being imported after cr_shared_vars and overriding the
correct values of --google- colors with incorrect ones. To fix this:
- Remove all --google- colors from paper-styles/color.js
- Move the 3 --google colors that weren't already in cr_shared_vars
  and are still used into cr_shared_vars.
- Also removing some additional unused paper- colors, while making
  the patch for paper-styles.color.js.

Bug: 40943652
Change-Id: I910c38b62d49baa3a854e879e173d950c9796d3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5426276


Reviewed-by: John Lee <johntlee@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1283979}