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/_EventTile.pcss

@@ -53,7 +53,7 @@ $left-gutter: 64px;
         height: 16px;
 
         &::before {
-            background-color: $tertiary-content;
+            background-color: var(--cpd-color-icon-tertiary);
             mask-repeat: no-repeat;
             mask-position: center;
             mask-size: 16px;
@@ -858,12 +858,12 @@ $left-gutter: 64px;
 
     &.mx_EventTile_e2eIcon_normal::after {
         mask-image: url("$(res)/img/e2e/normal.svg"); /* regular shield */
-        background-color: $header-panel-text-primary-color; /* grey */
+        background-color: var(--cpd-color-icon-tertiary); /* grey */
     }
 
     &.mx_EventTile_e2eIcon_decryption_failure::after {
         mask-image: url("$(res)/img/e2e/decryption-failure.svg"); /* key in a circle */
-        background-color: $secondary-content;
+        background-color: var(--cpd-color-icon-tertiary);
     }
 }