[web] Add collapsible info to ODC (#30164)

* Add collapsible info in ODC

* Remove transition effects on caret

* Update summary focus-visible style

Make it inline-block so the clickable part doesn't go out of bounds.
Update outline style.

* Make the caret orientation consistent with Figma and Dashboard

* Remove extra padding

* Make `summary` styled like ds btn-tertiary

See https://www.figma.com/design/qHqSob0u4b4h1i2ModSTLn/CIAM---Phase-01?node-id=2285-20806&t=AlQIeoQEd2kG2h2M-0

GitOrigin-RevId: 9a49efe68088ea4969a803ffaa1c981c5a7ed7bb

services/web/frontend/stylesheets/ciam/ciam-onboarding.scss

@@ -29,3 +29,26 @@
 .ciam-used-latex-options {
   padding-bottom: var(--ds-spacing-200);
 }
+
+details.ciam-onboarding-privacy {
+  summary {
+    padding: var(--ds-spacing-100) var(--ds-spacing-200);
+
+    @extend .btn, .btn-ds, .btn-tertiary;
+
+    svg {
+      margin-left: var(--ds-spacing-200);
+      color: var(--ds-color-text-secondary);
+
+      &.flip {
+        transform: rotate(180deg);
+      }
+    }
+  }
+
+  .ciam-onboarding-collapse-content {
+    margin: var(--ds-spacing-200) var(--ds-spacing-200) var(--ds-spacing-500);
+
+    @include ds-body-sm-regular;
+  }
+}