fix(server): limit rootDoc snapshot size (#12625)

close CLOUD-225

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

## Summary by CodeRabbit

- **New Features**
  - Added support for reading document blocks without requiring a workspace or root document snapshot.
- **Bug Fixes**
  - Improved handling of large workspace snapshots by skipping them when they exceed 10MB.
- **Tests**
  - Introduced new test cases to cover scenarios where root or workspace snapshots are absent.
  - Expanded snapshot tests for document block reading.
- **Refactor**
  - Updated several function signatures to make root and workspace snapshot parameters optional for greater flexibility.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/indexer/service.ts

@@ -226,11 +226,14 @@ export class IndexerService {
       this.logger.debug(`doc ${workspaceId}/${docId} is empty, skip indexing`);
       return;
     }
+    const MAX_WORKSPACE_SNAPSHOT_SIZE = 1024 * 1024 * 10; // 10MB
     const result = await readAllBlocksFromDocSnapshot(
       workspaceId,
-      workspaceSnapshot.blob,
       docId,
-      docSnapshot.blob
+      docSnapshot.blob,
+      workspaceSnapshot.blob.length < MAX_WORKSPACE_SNAPSHOT_SIZE
+        ? workspaceSnapshot.blob
+        : undefined
     );
     if (!result) {
       this.logger.warn(