fix(editor): should preserve format in <p> when importing html (#12275)

Closes: [BS-3485](https://linear.app/affine-design/issue/BS-3485/粘贴-html-格式的内容时，紧邻着-bold-text-的普通文本会丢失空格)

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

- **Bug Fixes**
  - Improved handling of spaces and whitespace in paragraphs when converting HTML with inline formatting, ensuring spaces are preserved as in the original content.

- **Tests**
  - Added a new test to verify that spaces are correctly preserved in paragraphs containing bold and italic formatting during HTML conversion.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/inlines/preset/src/adapters/html/html-inline.ts

@@ -5,6 +5,24 @@ import {
 import { collapseWhiteSpace } from 'collapse-white-space';
 import type { Element } from 'hast';
 
+/**
+ * Handle empty text nodes created by HTML parser for styling purposes.
+ * These nodes typically contain only whitespace/newlines, for example:
+ * ```json
+ * {
+ *   "type": "text",
+ *   "value": "\n\n  \n  \n  "
+ * }
+ * ```
+ * We collapse and trim the whitespace to check if the node is truly empty,
+ * and return an empty array in that case.
+ */
+const isEmptyText = (ast: HtmlAST): boolean => {
+  return (
+    ast.type === 'text' && collapseWhiteSpace(ast.value, { trim: true }) === ''
+  );
+};
+
 const isElement = (ast: HtmlAST): ast is Element => {
   return ast.type === 'element';
 };
@@ -22,12 +40,16 @@ export const htmlTextToDeltaMatcher = HtmlASTToDeltaExtension({
       return [];
     }
     const { options } = context;
-    options.trim ??= true;
+    options.trim ??= false;
 
     if (options.pre) {
       return [{ insert: ast.value }];
     }
 
+    if (isEmptyText(ast)) {
+      return [];
+    }
+
     const value = options.trim
       ? collapseWhiteSpace(ast.value, { trim: options.trim })
       : collapseWhiteSpace(ast.value);