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

src/components/views/dialogs/security/AccessSecretStorageDialog.tsx

@@ -430,7 +430,7 @@ export default class AccessSecretStorageDialog extends React.PureComponent<IProp
                             onPrimaryButtonClick={this.onRecoveryKeyNext}
                             hasCancel={true}
                             cancelButton={_t("action|go_back")}
-                            cancelButtonClass="danger"
+                            cancelButtonClass="warning"
                             onCancel={this.onCancel}
                             focus={false}
                             primaryDisabled={!this.state.recoveryKeyValid}