fix(core): loading spinner color issue (#13192)

#### PR Dependency Tree


* **PR #13192** 👈

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[Charcoal](https://github.com/danerwilliams/charcoal)

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## Summary by CodeRabbit

* **Style**
* Updated the loading icon to ensure consistent appearance by explicitly
setting the fill property to none using an inline style.

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

blocksuite/affine/components/src/icons/loading.ts

@@ -18,6 +18,7 @@ export const LoadingIcon = ({
     viewBox="0 0 24 24"
     xmlns="http://www.w3.org/2000/svg"
     fill="none"
+    style="fill: none;"
   >
     <style>
       .spinner {