MOBILE-4270 forum: Fix discussion link handler in tablet

This part of code changed in 1fbb4c3880 to fix navigation, but now it didn't work in tablets because it tried to load the forum index page. Maybe this change breaks a case we haven't detected

src/addons/mod/forum/services/handlers/discussion-link.ts

@@ -65,12 +65,8 @@ export class AddonModForumDiscussionLinkHandlerService extends CoreContentLinksH
                     pageParams.parent = parseInt(params.parent);
                 }
 
-                const path = cmId && courseId
-                    ? `${AddonModForumModuleHandlerService.PAGE_NAME}/${courseId}/${cmId}/${discussionId}`
-                    : `${AddonModForumModuleHandlerService.PAGE_NAME}/discussion/${discussionId}`;
-
                 CoreNavigator.navigateToSitePath(
-                    path,
+                    `${AddonModForumModuleHandlerService.PAGE_NAME}/discussion/${discussionId}`,
                     { siteId, params: pageParams },
                 );
             },