fix(S3#_list): handle remote without base directory (#6218)

Related to zammad#6740

@xen-orchestra/fs/src/s3.js

@@ -97,7 +97,12 @@ export default class S3Handler extends RemoteHandlerAbstract {
   }
 
   _makePrefix(dir) {
-    return join(this._dir, dir, '/')
+    const prefix = join(this._dir, dir, '/')
+
+    // no prefix for root
+    if (prefix !== './') {
+      return prefix
+    }
   }
 
   _createParams(file) {

CHANGELOG.unreleased.md

@@ -15,6 +15,8 @@
 
 > Users must be able to say: “I had this issue, happy to know it's fixed”
 
+- [S3] Fix S3 remote with empty directory not showing anything to restore (PR [#6218](https://github.com/vatesfr/xen-orchestra/pull/6218))
+
 ### Packages to release
 
 > Packages will be released in the order they are here, therefore, they should