feat(app): fix file tree button bg (#38629)

Author: arvsrn

packages/session-ui/src/v2/components/session-review-v2.css

@@ -244,7 +244,7 @@
 }
 
 [data-component="icon-button-v2"][data-variant="ghost"].session-review-v2-sidebar-toggle[aria-expanded="true"] {
-  background-color: var(--v2-overlay-simple-overlay-pressed);
+  background-color: var(--v2-background-bg-layer-02);
 }
 
 [data-component="session-review-v2"] [data-slot="session-review-v2-file-header"] {

packages/session-ui/src/v2/components/session-review-v2.tsx

@@ -333,6 +333,7 @@ export function SessionReviewV2SidebarToggle(props: { opened: boolean; disabled?
         class="session-review-v2-sidebar-toggle"
         aria-label={i18n.t("ui.sessionReviewV2.toggleSidebar")}
         aria-expanded={props.opened}
+        data-expanded={props.opened ? "" : undefined}
         disabled={props.disabled}
         onClick={props.onToggle}
         icon={<Icon name="filetree" />}