Fix: Use rawComment.body in applySuggestionWithCopilot to exclude AI warning suffix

When applying a suggestion using AI for Copilot Code Review comments,
the rendered comment body included the "Copilot is powered by AI, so
mistakes are possible" suffix. Use rawComment.body instead to get the
original comment text without the display-only warning.

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>
Agent-Logs-Url: https://github.com/microsoft/vscode-pull-request-github/sessions/a47a6887-194e-4dd7-966a-3459c61cc24c

Author: Copilot

src/commands.ts

@@ -1848,9 +1848,10 @@ ${contents}
 
 			const isThread = GHPRCommentThread.is(comment);
 			const commentThread = isThread ? comment : comment.parent;
-			const commentBody = isThread ? comment.comments[0].body : comment.body;
+			const firstComment = isThread ? comment.comments[0] : comment;
 			commentThread.collapsibleState = vscode.CommentThreadCollapsibleState.Collapsed;
-			const message = commentBody instanceof vscode.MarkdownString ? commentBody.value : commentBody;
+			const message = firstComment instanceof GHPRComment ? firstComment.rawComment.body
+				: (firstComment.body instanceof vscode.MarkdownString ? firstComment.body.value : firstComment.body);
 
 			if (isThread) {
 				// For threads, open the Chat view instead of inline chat