[BUGFIX] Using ext:sys_action gives a warning about not valid HTML

When ext:sys_action is installed it will give a warning about
not valid HTML. This is because the id="" and class="" are glued
to each other. Fix this by moving the space from the front to the
back.

Change-Id: Ia916a9e084cb9f3595164215cf22a100d64dc7a9
Resolves: #52202
Releases: 6.2
Reviewed-on: https://review.typo3.org/24001
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer

typo3/sysext/sys_action/Classes/ActionToolbarMenu.php

@@ -132,7 +132,7 @@ class ActionToolbarMenu implements \TYPO3\CMS\Backend\Toolbar\ToolbarItemHookInt
 	 * @return string List item HTML attibutes
 	 */
 	public function getAdditionalAttributes() {
-		return ' id="tx-sys-action-menu"';
+		return 'id="tx-sys-action-menu" ';
 	}
 
 	/**