enhance(web): hide attachment dropzone on preview tab in combo editor (#39204)

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/issue/fields/textarea.tmpl

@@ -16,7 +16,7 @@
 		)}}
 
 		{{if .root.IsAttachmentEnabled}}
-		<div class="tw-mt-4 form-field-dropzone tw-hidden">
+		<div class="tw-mt-4 form-field-dropzone tw-hidden">{{/*TODO: need to refactor the "repo/upload" template and remove this wrapper */}}
 			{{template "repo/upload" .root}}
 		</div>
 		{{end}}

templates/repo/upload.tmpl

@@ -1,5 +1,5 @@
 <div
-	class="ui dropzone"
+	class="dropzone"
 	data-link-url="{{.UploadLinkUrl}}"
 	data-upload-url="{{.UploadUrl}}"
 	data-remove-url="{{.UploadRemoveUrl}}"