fix(editor): footnote popup style and position issues (#11771)

Close [BS-3049](https://linear.app/affine-design/issue/BS-3049/chat引用的样式坏了) [BS-3024](https://linear.app/affine-design/issue/BS-3024/footnote-在容器边缘时，hover-抽搐)

blocksuite/affine/fragments/outline/src/card/outline-preview.css.ts

@@ -1,6 +1,6 @@
 import { cssVar } from '@toeverything/theme';
 import { cssVarV2 } from '@toeverything/theme/v2';
-import { style } from '@vanilla-extract/css';
+import { globalStyle, style } from '@vanilla-extract/css';
 
 export const outlineBlockPreview = style({
   fontFamily: cssVar('fontFamily'),
@@ -108,6 +108,11 @@ export const linkedDocPreviewUnavailable = style({
   color: cssVarV2('text/disable'),
 });
 
+export const linkedDocPreviewAvailable = style({});
+globalStyle(`${linkedDocPreviewAvailable} > svg`, {
+  marginBottom: '0.1em',
+});
+
 export const linkedDocTextUnavailable = style({
   color: cssVarV2('text/disable'),
   textDecoration: 'line-through',

blocksuite/affine/fragments/outline/src/card/outline-preview.ts

@@ -67,6 +67,7 @@ export class OutlineBlockPreview extends SignalWatcher(
         return html`<span
           class=${classMap({
             [styles.linkedDocPreviewUnavailable]: unavailable,
+            [styles.linkedDocPreviewAvailable]: !unavailable,
           })}
         >
           ${icon}