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/css/views/rooms/_TopUnreadMessagesBar.pcss

@@ -40,7 +40,7 @@ limitations under the License.
     border-radius: 19px;
     box-sizing: border-box;
     background: $background;
-    border: 1.3px solid $muted-fg-color;
+    border: 1.3px solid var(--cpd-color-icon-tertiary);
     cursor: pointer;
 }
 
@@ -53,7 +53,7 @@ limitations under the License.
     mask-repeat: no-repeat;
     mask-size: 20px;
     mask-position: center;
-    background: $muted-fg-color;
+    background: var(--cpd-color-icon-tertiary);
 }
 
 .mx_TopUnreadMessagesBar_markAsRead {
@@ -61,7 +61,7 @@ limitations under the License.
     width: 18px;
     height: 18px;
     background: $background;
-    border: 1.3px solid $muted-fg-color;
+    border: 1.3px solid var(--cpd-color-icon-tertiary);
     border-radius: 10px;
     margin: 5px auto;
 }
@@ -75,5 +75,5 @@ limitations under the License.
     mask-repeat: no-repeat;
     mask-size: 10px;
     mask-position: 4px 4px;
-    background: $muted-fg-color;
+    background: var(--cpd-color-icon-tertiary);
 }