Regression: dropdowns no longer look the same

Rebased.

Before

After

hm a few thoughts. "technically" sort by is not a button but a select field so the greyish regular button background feels off and semantically wrong. while on the other hand the grey for the filter is semantically correct since it is a toggle button. but that filter button has a border (#919297) buttons usually dont have according to the drupal design system? also on hover that border gets solid dark/black instead of changing the background to a darker grey, also not in line with the drupal design system. i am not sure if styling the filter toggle button and the select field the same way is the right call here. those are different kinds of interface elements. and from an accessibility point view the background of the select field (#D3D4D9) against the filter section background (#F3F4F9) results in 1.3:1 , WCAG 2.2. SC 1.4.11 would require at least a color contrast of 3:1. the filter toggle button would have the same issue but with the border in place it is "slightly" better but still not meeting SC1.4.11. border (#919297) against the filter section background (#F3F4F9) has 2.8:1 and border (#919297) against filter section background (#F3F4F9) gets 2.1:1. and then there is also #3318817: Improve the categories filter type in context to the rest of the filter component ui which would change that entire filter section. and strictly speaking the sort select field wouldnt be part of the filter section anymore since it gets untwined.

After looking into this issue, It seems to have accomplished the requirements. I tested it with drupalPod.
Hence, I'm setting it to RTBC.
I agree with @rkoller on most suggested changes but we are likely to address those in a follow-up ticket. I can open that.
Additionally, we will likely have to roll out the Drupal design systems everywhere once we are ready to be merged into Drupal core. So it might be postponed a little but it's coming. #331817 is not ready yet, but it is a good idea to reference it.