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/image/src/image-block.ts

@@ -9,7 +9,7 @@ import {
   ThemeProvider,
   ToolbarRegistryIdentifier,
 } from '@blocksuite/affine-shared/services';
-import { humanFileSize } from '@blocksuite/affine-shared/utils';
+import { formatSize } from '@blocksuite/affine-shared/utils';
 import { IS_MOBILE } from '@blocksuite/global/env';
 import { BrokenImageIcon, ImageIcon } from '@blocksuite/icons/lit';
 import { BlockSelection } from '@blocksuite/std';
@@ -142,7 +142,7 @@ export class ImageBlockComponent extends CaptionedBlockComponent<ImageBlockModel
       errorIcon: BrokenImageIcon(),
       icon: ImageIcon(),
       title: 'Image',
-      description: humanFileSize(size),
+      description: formatSize(size),
     });
 
     return html`

blocksuite/affine/blocks/image/src/image-edgeless-block.ts

@@ -8,7 +8,7 @@ import {
 } from '@blocksuite/affine-model';
 import { ThemeProvider } from '@blocksuite/affine-shared/services';
 import { unsafeCSSVarV2 } from '@blocksuite/affine-shared/theme';
-import { humanFileSize } from '@blocksuite/affine-shared/utils';
+import { formatSize } from '@blocksuite/affine-shared/utils';
 import { BrokenImageIcon, ImageIcon } from '@blocksuite/icons/lit';
 import { GfxBlockComponent } from '@blocksuite/std';
 import { GfxViewInteractionExtension } from '@blocksuite/std/gfx';
@@ -128,7 +128,7 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
       errorIcon: BrokenImageIcon(),
       icon: ImageIcon(),
       title: 'Image',
-      description: humanFileSize(size),
+      description: formatSize(size),
     });
 
     return html`

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

@@ -11,8 +11,8 @@ import {
   NativeClipboardProvider,
 } from '@blocksuite/affine-shared/services';
 import {
+  formatSize,
   getBlockProps,
-  humanFileSize,
   isInsidePageEditor,
   readImageSize,
   transformModel,
@@ -241,7 +241,7 @@ 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}`);
   }