Fix layouts of admin table / adapt repo / email test (#24370)

Ref:
https://github.com/go-gitea/gitea/pull/24315#pullrequestreview-1403034993

And fix the incorrect layout for "dasbboard", the "form" shouldn't
follow `<h4 class="ui top attached header">`, so move it to inner.

Diff with ignoring spaces:
https://github.com/go-gitea/gitea/pull/24370/files?diff=unified&w=1

A known bug: the adapt/delete button doesn't work due to a historical
messy logic, will fix it in next PR (#24374)

![image](https://user-images.githubusercontent.com/2114189/234754656-d160b098-b8d4-4783-962a-27d5c764863c.png)

![image](https://user-images.githubusercontent.com/2114189/234762327-3e77e2e4-a156-4498-8a8b-092e14cf9204.png)

![image](https://user-images.githubusercontent.com/2114189/234767811-74b7272c-e40c-4850-8e3c-499e3b53b827.png)

![image](https://user-images.githubusercontent.com/2114189/234761247-e6aad889-dcad-443c-948f-2d44df68725b.png)

templates/admin/dashboard.tmpl

@@ -16,9 +16,9 @@
 		<h4 class="ui top attached header">
 			{{.locale.Tr "admin.dashboard.operations"}}
 		</h4>
-		<form method="post" action="{{AppSubUrl}}/admin">
-			{{.CsrfTokenHtml}}
-			<div class="ui attached table segment">
+		<div class="ui attached table segment">
+			<form method="post" action="{{AppSubUrl}}/admin">
+				{{.CsrfTokenHtml}}
 				<table class="ui very basic table gt-px-4">
 					<tbody>
 						<tr>
@@ -71,8 +71,8 @@
 						</tr>
 					</tbody>
 				</table>
-			</div>
-		</form>
+			</form>
+		</div>
 
 		<h4 class="ui top attached header">
 			{{.locale.Tr "admin.dashboard.system_status"}}