Speed up granting permissions to users in webdriver tests

The webdriver method granting permissions to users freezes for around 6 seconds when adding a permission to a user (in ITSearchTabTest for instance).

This is linked to the "wait for permission added" logic in PermissionsSubPage#hasPermissionForUser

List<WebElement> spans = element.findElements(new ByChained(By.tagName("div"), By.tagName("span")));

This takes around 4 seconds, the ByChained find seems costly and matches much more elements than what the test actually needs to check.

Additionnal 2 seconds are linked to a missing break when iterating over these elements.