Use new property for admin user indication

is_admin field inside UserExtraInfo is deprecated now.
We use dedicated IsAdminUser property in CheckFileInfo instead.
Leave old code for now for backward compatibility.

see: CollaboraOnline/online#9242

Signed-off-by: Szymon Kłos <szymon.klos@collabora.com>

lib/Controller/WopiController.php

@@ -197,13 +197,16 @@ public function checkFileInfo($fileId, $access_token) {
 		if ($user !== null) {
 			$response['UserExtraInfo']['avatar'] = $this->urlGenerator->linkToRouteAbsolute('core.avatar.getAvatar', ['userId' => $wopi->getEditorUid(), 'size' => self::WOPI_AVATAR_SIZE]);
 			if ($this->groupManager->isAdmin($wopi->getEditorUid())) {
-				$response['UserExtraInfo']['is_admin'] = true;
+				$response['UserExtraInfo']['is_admin'] = true; // DEPRECATED
+				$response['IsAdminUser'] = true;
 			} else {
-				$response['UserExtraInfo']['is_admin'] = false;
+				$response['UserExtraInfo']['is_admin'] = false; // DEPRECATED
+				$response['IsAdminUser'] = false;
 			}
 		} else {
 			$response['UserExtraInfo']['avatar'] = $this->urlGenerator->linkToRouteAbsolute('core.GuestAvatar.getAvatar', ['guestName' => urlencode($wopi->getGuestDisplayname()), 'size' => self::WOPI_AVATAR_SIZE]);
-			$response['UserExtraInfo']['is_admin'] = false;
+			$response['UserExtraInfo']['is_admin'] = false; // DEPRECATED
+			$response['IsAdminUser'] = false;
 		}
 
 		if ($isPublic) {