Remove eye dropper icon as background img and define color for hue ring

This CL appends the eye dropper icon to the tree instead of inserting it
as a background image so that when users apply high contrast modes, the
`WindowText` color is correctly rendered on Windows. Additionally, the
color selection ring's color when focused is defined under the media
query `forced-colors: active` so that proper contrast is rendered.

With this change and contrast modes applied, the color picker UI looks:
Aquatic
https://drive.google.com/file/d/1c3v-mCtOXTQ20sPP35pizq3Jzy9SWJle/view?usp=sharing
Desert:
https://drive.google.com/file/d/1hrXqFYco2wr4li1hW_x6k_2a9CFNWK7L/view?usp=sharing

Baselines had to be updated due to minimal differences in how the eye
dropper icon looks. Example:
https://ci.chromium.org/ui/p/chromium/builders/try/win11-arm64-blink-rel/3456/overview/.

Relevant existing test: `color-picker-appearance.html`, `virtual suites:
virtual/controls-refresh-hc`, `virtual/dark-color-scheme`.

Bug: 394634487
Change-Id: Iea5b5d89275b1873eaf40473cbed934c8ae63940
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6249670
Reviewed-by: Sanket Joshi <sajos@microsoft.com>
Reviewed-by: Mason Freed <masonf@chromium.org>
Commit-Queue: Ana Sollano Kim <ansollan@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1422917}