Make sure all text nodes in chat markdown are wrapped in elements (#264049)

For #264043

I'm pretty sure the tests where showing bugs where top level text nodes weren't being replaces

Author: mjbvz

src/vs/workbench/contrib/chat/browser/chatMarkdownRenderer.ts

@@ -97,13 +97,14 @@ export class ChatMarkdownRenderer extends MarkdownRenderer {
 			: markdown;
 		const result = super.render(mdWithBody, options, outElement);
 
-		// In some cases, the renderer can return text that is not inside a <p>,
-		// but our CSS expects text to be in a <p> for margin to be applied properly.
+		// In some cases, the renderer can return top level text nodes  but our CSS expects
+		// all text to be in a <p> for margin to be applied properly.
 		// So just normalize it.
 		result.element.normalize();
-		const lastChild = result.element.lastChild;
-		if (lastChild?.nodeType === Node.TEXT_NODE && lastChild.textContent?.trim()) {
-			lastChild.replaceWith($('p', undefined, lastChild.textContent));
+		for (const child of result.element.childNodes) {
+			if (child.nodeType === Node.TEXT_NODE && child.textContent?.trim()) {
+				child.replaceWith($('p', undefined, child.textContent));
+			}
 		}
 		return this.attachCustomHover(result);
 	}

src/vs/workbench/contrib/chat/test/browser/__snapshots__/ChatMarkdownRenderer_html_comments.0.snap

@@ -1,3 +1,3 @@
-<div class="rendered-markdown">
+<div class="rendered-markdown"><p>
 
-&lt;!-- comment1 &lt;div&gt;&lt;/div&gt; --&gt;<div>content</div><p>&lt;!-- comment2 --&gt;</p></div>
+&lt;!-- comment1 &lt;div&gt;&lt;/div&gt; --&gt;</p><div>content</div><p>&lt;!-- comment2 --&gt;</p></div>

src/vs/workbench/contrib/chat/test/browser/__snapshots__/ChatMarkdownRenderer_invalid_HTML.0.snap

@@ -1,3 +1,3 @@
 <div class="rendered-markdown">
 
-<p>1&lt;canvas&gt;2&lt;/canvas&gt;</p>&lt;details&gt;3&lt;/details&gt;4<p></p></div>
+<p>1&lt;canvas&gt;2&lt;/canvas&gt;</p><p>&lt;details&gt;3&lt;/details&gt;4</p><p></p></div>

src/vs/workbench/contrib/chat/test/browser/__snapshots__/ChatMarkdownRenderer_invalid_HTML_with_attributes.0.snap

@@ -1,3 +1,3 @@
 <div class="rendered-markdown">
 
-<p>1</p>&lt;details id="id1" style="display: none"&gt;2&lt;details id="my id 2"&gt;3&lt;/details&gt;&lt;/details&gt;4<p></p></div>
+<p>1</p><p>&lt;details id="id1" style="display: none"&gt;2&lt;details id="my id 2"&gt;3&lt;/details&gt;&lt;/details&gt;4</p><p></p></div>

src/vs/workbench/contrib/chat/test/browser/__snapshots__/ChatMarkdownRenderer_mixed_valid_and_invalid_HTML.0.snap

@@ -1,11 +1,11 @@
 <div class="rendered-markdown">
 
 
-<h1>heading</h1>
+<h1>heading</h1><p>
 &lt;details&gt;
-<ul>
+</p><ul>
     <li><span>&lt;details&gt;<i>1</i>&lt;/details&gt;</span></li>
     <li><b>hi</b></li>
-</ul>
+</ul><p>
 &lt;/details&gt;
-<pre>&lt;canvas&gt;canvas here&lt;/canvas&gt;</pre><p>&lt;details&gt;&lt;/details&gt;</p></div>
+</p><pre>&lt;canvas&gt;canvas here&lt;/canvas&gt;</pre><p>&lt;details&gt;&lt;/details&gt;</p></div>

src/vs/workbench/contrib/chat/test/browser/__snapshots__/ChatMarkdownRenderer_self-closing_elements.0.snap

@@ -1,3 +1,3 @@
 <div class="rendered-markdown">
 
-<p>&lt;area&gt;</p><hr><br>&lt;input value="test" type="text"&gt;<p></p></div>
+<p>&lt;area&gt;</p><hr><br><p>&lt;input value="test" type="text"&gt;</p><p></p></div>