Fix share permissions rendering

The `SHARE` permissions falls into the `default` case in the switch case, causing the rendering to look like ` , Upload, Read`.

This PR changes the return value of the `default` case and adds a `filter` to remove those values.

Signed-off-by: Louis Chemineau <louis@chmn.me>

apps/files_sharing/src/components/SharePermissionsEditor.vue

@@ -163,9 +163,10 @@ export default {
 					case this.atomicPermissions.DELETE:
 						return this.t('files_sharing', 'Delete')
 					default:
-						return ''
+						return null
 					}
 				})
+				.filter(permissionLabel => permissionLabel !== null)
 				.join(', ')
 		},