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/shared/package.json

@@ -22,6 +22,7 @@
     "@types/hast": "^3.0.4",
     "@types/lodash-es": "^4.17.12",
     "@types/mdast": "^4.0.4",
+    "bytes": "^3.1.2",
     "dompurify": "^3.2.4",
     "fractional-indexing": "^3.2.0",
     "lit": "^3.2.0",
@@ -70,6 +71,7 @@
     "!dist/__tests__"
   ],
   "devDependencies": {
+    "@types/bytes": "^3.1.5",
     "vitest": "3.1.3"
   },
   "version": "0.21.0"