Change the style in admin notice content view from <p> to <pre> (#11301)

That's because many notic have more than one lines. So I think
pre is more better to used in here than p

Signed-off-by: a1012112796 <1012112796@qq.com>

templates/admin/notice.tmpl

@@ -77,7 +77,7 @@
 	<i class="close icon"></i>
 	<div class="header">{{$.i18n.Tr "admin.notices.view_detail_header"}}</div>
 	<div class="content">
-		<p></p>
+		<pre></pre>
 	</div>
 </div>
 {{template "base/footer" .}}