Refine the colors of some more components (#12343)

* Refine the colors of some more components

This is a reintroduction of https://github.com/matrix-org/matrix-react-sdk/pull/12255, and should be the last part of the Compound color refinement work (https://github.com/element-hq/element-web/issues/26992). I've updated the following components to reflect design decisions (https://www.figma.com/file/pqhlirZFEwEp5XpudSbiia/Theming-Web-templates?type=design&node-id=80-60219&mode=design&t=mjqwylUie1vRwzOV-0) that will help them fit in better with the new design system:

- Message bubbles
- Pills
- Sent indicators
- Jump to bottom/unread buttons
- Composer placeholder
- Notification badges
- Room sublists
- Verification shields
- Date separators
- Tooltips

Closes https://github.com/element-hq/element-web/issues/22122

* Update some screenshots

res/themes/light-custom/css/_custom.pcss

@@ -116,7 +116,6 @@ $settings-grey-fg-color: $primary-content;
 $eventbubble-self-bg: var(--eventbubble-self-bg, $eventbubble-self-bg);
 $eventbubble-others-bg: var(--eventbubble-others-bg, $eventbubble-others-bg);
 $eventbubble-bg-hover: var(--eventbubble-bg-hover, $eventbubble-bg-hover);
-$eventbubble-reply-color: var(--eventbubble-reply-color, $eventbubble-reply-color);
 
 $reaction-row-button-selected-bg-color: var(
     --reaction-row-button-selected-bg-color,