chore(editor): change edgeless-text default color to black (#12361)

Closes: [BS-3506](https://linear.app/affine-design/issue/BS-3506/edgeless-text-默认改为黑色)

### Dark
<img width="691" alt="Screenshot 2025-05-19 at 19 32 52" src="https://github.com/user-attachments/assets/2927d13b-0300-4293-8f8f-7891fd87a680" />

### Light
<img width="639" alt="Screenshot 2025-05-19 at 19 33 05" src="https://github.com/user-attachments/assets/4429f6f9-b374-4b17-87f4-ae09204f1538" />

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

## Summary by CodeRabbit

- **New Features**
  - Improved edgeless text block styling to support theme-based color, font, and alignment settings.

- **Style**
  - Updated the default text color in edgeless text blocks to black, with support for separate dark and light mode colors.

- **Bug Fixes**
  - Ensured the color picker and block rendering reflect the updated default color.

- **Tests**
  - Adjusted tests and snapshots to expect the new default color and theme-based color structure.

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

blocksuite/affine/gfx/text/src/edgeless-text-editor.ts

@@ -6,7 +6,7 @@ import {
   type IModelCoord,
   TextUtils,
 } from '@blocksuite/affine-block-surface';
-import { TextElementModel } from '@blocksuite/affine-model';
+import { DefaultTheme, TextElementModel } from '@blocksuite/affine-model';
 import type { RichText } from '@blocksuite/affine-rich-text';
 import { ThemeProvider } from '@blocksuite/affine-shared/services';
 import { getSelectedRect } from '@blocksuite/affine-shared/utils';
@@ -432,7 +432,7 @@ export class EdgelessTextEditor extends WithDisposable(ShadowlessElement) {
     const isEmpty = !text.length && !this._isComposition;
     const color = this.std
       .get(ThemeProvider)
-      .generateColorProperty(this.element.color, '#000000');
+      .generateColorProperty(this.element.color, DefaultTheme.textColor);
 
     return html`<div
       style=${styleMap({