fix(editor): unify file size formatting method (#12444)

Closes: [BS-3524](https://linear.app/affine-design/issue/BS-3524/统一文件大小单位，与-af-一致)

![Screenshot 2025-05-22 at 15.09.41.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/8ypiIKZXudF5a0tIgIzf/ddb6fa38-243f-4e65-b572-d476e3771d74.png)

![Screenshot 2025-05-22 at 15.09.48.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/8ypiIKZXudF5a0tIgIzf/5d182332-4d0a-419a-b206-df58552fe740.png)

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

- **Refactor**
  - Updated file size formatting throughout the app to use a new, consistent utility for displaying file sizes.
  - Improved clarity and uniformity of file size information in attachments, images, and related notifications.
  - Enhanced type support to explicitly allow null values for file size descriptions.
- **Bug Fixes**
  - Adjusted file size display in tests to match updated formatting standards.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/attachment/src/utils.ts

@@ -13,7 +13,7 @@ import {
   FileSizeLimitProvider,
   TelemetryProvider,
 } from '@blocksuite/affine-shared/services';
-import { humanFileSize } from '@blocksuite/affine-shared/utils';
+import { formatSize } from '@blocksuite/affine-shared/utils';
 import { Bound, type IVec, Vec } from '@blocksuite/global/gfx';
 import type { BlockStdScope } from '@blocksuite/std';
 import { GfxControllerIdentifier } from '@blocksuite/std/gfx';
@@ -93,7 +93,7 @@ function hasExceeded(
   const exceeded = files.some(file => file.size > maxFileSize);
 
   if (exceeded) {
-    const size = humanFileSize(maxFileSize, true, 0);
+    const size = formatSize(maxFileSize);
     toast(std.host, `You can only upload files less than ${size}`);
   }