refactor(editor): get loading icon with theme (#12079)

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

- **New Features**
  - Introduced a unified loading spinner icon that adapts to light or dark themes automatically.

- **Refactor**
  - Streamlined loading icon usage across the app by replacing multiple theme-based icons with a single helper function for consistent and simplified icon management.

- **Chores**
  - Removed an unused dependency to improve package management.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/attachment/tsconfig.json

@@ -7,7 +7,6 @@
   },
   "include": ["./src"],
   "references": [
-    { "path": "../embed" },
     { "path": "../surface" },
     { "path": "../../components" },
     { "path": "../../ext-loader" },