[a11y] Dropbutton issues in forced colors mode

MR fixes the problems in the IS

Chevron is visible, list is outlined, messy border/outlines fixed

Hover effect for items

Focus effect for items

Hi,

Tested the MR !278 to address the issue drop button issues in forced color mode. it's works fine, all issue points (chevron icon visibility, Hover/Focus state ) are covered in MR:

Testing Steps:
1. Install the Drupal 10.0.x version and enable gin 8.x.
2. on path admin/structure/types/manage/article/fields, enable the force color mode.
3. Switch to MR and verified the changes in update MR.

attached the screen for references.
Beore:

After:

Looks Good for RTBC

Based on the comment in #4, the intent was to RTBC but the status was not changed, so I am changing it.

Thanks 💪

Automatically closed - issue fixed for 2 weeks with no activity.