fix(editor): loading style (#12537)

Closes: [BS-3555](https://linear.app/affine-design/issue/BS-3555/ui-attachment-loading-变量更新)
Closes: [BS-3559](https://linear.app/affine-design/issue/BS-3559/ui-图片-loading-变量更新)

### Dark
<img width="625" alt="Screenshot 2025-05-26 at 20 32 36" src="https://github.com/user-attachments/assets/93501e3d-8fc6-45f9-84a0-ac147e5c5f9f" />

### Light
<img width="623" alt="Screenshot 2025-05-26 at 20 32 25" src="https://github.com/user-attachments/assets/7d5bc128-6667-45b5-982d-dab3a22706a7" />

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

- **New Features**
  - Loading icons are now invoked as functions, allowing for more flexible and customizable rendering with parameters like size and progress.

- **Refactor**
  - Replaced theme-dependent and static loading icon references with a unified `LoadingIcon()` component across multiple components and blocks.
  - Removed legacy icon variants and simplified icon import statements, centralizing icon rendering logic.

- **Style**
  - Updated styles for loading and reload buttons to use theme-aware CSS variables.
  - Enlarged and repositioned loading indicators in image blocks for better visibility.

- **Bug Fixes**
  - Achieved consistent loading icon rendering across various blocks and components by standardizing icon invocation.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/embed/src/embed-iframe-block/components/embed-iframe-loading-card.ts

@@ -1,4 +1,4 @@
-import { ThemeProvider } from '@blocksuite/affine-shared/services';
+import { LoadingIcon } from '@blocksuite/affine-components/icons';
 import { unsafeCSSVarV2 } from '@blocksuite/affine-shared/theme';
 import { EmbedIcon } from '@blocksuite/icons/lit';
 import { type BlockStdScope } from '@blocksuite/std';
@@ -7,7 +7,6 @@ import { property } from 'lit/decorators.js';
 import { classMap } from 'lit/directives/class-map.js';
 import { styleMap } from 'lit/directives/style-map.js';
 
-import { getEmbedCardIcons } from '../../common/utils';
 import { LOADING_CARD_DEFAULT_HEIGHT } from '../consts';
 import type { EmbedIframeStatusCardOptions } from '../types';
 
@@ -156,9 +155,6 @@ export class EmbedIframeLoadingCard extends LitElement {
   `;
 
   override render() {
-    const theme = this.std.get(ThemeProvider).theme;
-    const { LoadingIcon } = getEmbedCardIcons(theme);
-
     const { layout, width, height } = this.options;
     const cardClasses = classMap({
       'affine-embed-iframe-loading-card': true,
@@ -176,7 +172,7 @@ export class EmbedIframeLoadingCard extends LitElement {
     return html`
       <div class=${cardClasses} style=${cardStyle}>
         <div class="loading-content">
-          <div class="loading-spinner">${LoadingIcon}</div>
+          <div class="loading-spinner">${LoadingIcon()}</div>
           <div class="loading-text">Loading...</div>
         </div>
         <div class="loading-banner">