Disable update checker on Flatpak (#3051)

Co-authored-by: Felanbird <41973452+Felanbird@users.noreply.github.com>
Co-authored-by: pajlada <rasmus.karlsson@pajlada.com>

src/singletons/Updates.cpp

@@ -240,6 +240,12 @@ void Updates::checkForUpdates()
         return;
     }
 
+    // Disable updates on Flatpak
+    if (QFileInfo::exists("/.flatpak-info"))
+    {
+        return;
+    }
+
     // Disable updates if on nightly
     if (Modes::instance().isNightly)
     {