Fix issue attachment handling (#24202) (#24221)

Backport #24202

Close #24195

Fix the bug:

1. The old code doesn't handle `removedfile` event correctly
2. The old code doesn't provide attachments for type=CommentTypeReview

---------

Co-authored-by: silverwind <me@silverwind.io>

templates/repo/issue/view_content/attachments.tmpl

@@ -1,11 +1,11 @@
 <div class="dropzone-attachments">
 	{{if .Attachments}}
-		<div class="ui clearing divider"></div>
+		<div class="ui divider"></div>
 	{{end}}
-	<div class="ui middle aligned padded grid">
-		{{$hasThumbnails := false}}
-		{{- range .Attachments -}}
-			<div class="twelve wide column" style="padding: 6px;">
+	{{$hasThumbnails := false}}
+	{{- range .Attachments -}}
+		<div class="gt-df">
+			<div class="gt-f1 gt-p-3">
 				<a target="_blank" rel="noopener noreferrer" href="{{.DownloadURL}}" title='{{$.ctx.locale.Tr "repo.issues.attachment.open_tab" .Name}}'>
 					{{if FilenameIsImage .Name}}
 						{{if not (containGeneric $.Content .UUID)}}
@@ -18,14 +18,14 @@
 					<span><strong>{{.Name}}</strong></span>
 				</a>
 			</div>
-			<div class="four wide column" style="padding: 0px;">
+			<div class="gt-p-3 gt-df gt-ac">
 				<span class="ui text grey right">{{.Size | FileSize}}</span>
 			</div>
-		{{end -}}
-	</div>
+		</div>
+	{{end -}}
 
 	{{if $hasThumbnails}}
-		<div class="ui clearing divider"></div>
+		<div class="ui divider"></div>
 		<div class="ui small thumbnails">
 			{{- range .Attachments -}}
 				{{if FilenameIsImage .Name}}