feat(editor): add collapse/expand toggle for groups with caching (#12671)

https://github.com/user-attachments/assets/4ef71704-57bb-45b8-9e73-8a51c67fb158

Adds a collapsible toggle for group-by groups.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Collapsible groups for desktop and mobile table views with persistent
per-view collapsed state and a keyboard-accessible toggle button.

- **Bug Fixes**
  - Group title icons now render consistently across variants.

- **Tests**
- Added unit tests verifying collapse/expand behavior for group
components.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: 3720 <zuozijian1994@gmail.com>
Co-authored-by: L-Sun <zover.v@gmail.com>

blocksuite/affine/data-view/src/core/group-by/group-title.ts

@@ -26,13 +26,10 @@ const GroupTitleMobile = (
   const type = groupData.tType;
   if (!type) return nothing;
 
-  const icon =
-    groupData.value == null
-      ? ''
-      : html` <uni-lit
-          class="group-header-icon"
-          .uni="${groupData.property.icon}"
-        ></uni-lit>`;
+  const icon = html` <uni-lit
+    class="group-header-icon"
+    .uni="${groupData.property.icon}"
+  ></uni-lit>`;
   const props: GroupRenderProps = {
     group: groupData,
     readonly: ops.readonly,
@@ -126,13 +123,10 @@ export const GroupTitle = (
   const type = groupData.tType;
   if (!type) return nothing;
 
-  const icon =
-    groupData.value == null
-      ? ''
-      : html` <uni-lit
-          class="group-header-icon"
-          .uni="${groupData.property.icon}"
-        ></uni-lit>`;
+  const icon = html` <uni-lit
+    class="group-header-icon"
+    .uni="${groupData.property.icon}"
+  ></uni-lit>`;
   const props: GroupRenderProps = {
     group: groupData,
     readonly: ops.readonly,