Fix custom game paths being lost after restart

[Lyapsus]

A custom Spore or Galactic Adventures path set in the settings only lasts until the next restart. GameManager.initialize() sets isSporeAuto/isGAAuto to true when the path read from config.properties validates, so the next saveSettings() writes AUTO back. On Windows the registry detection hides this; on Linux (Steam under Proton) the game is gone after every second launch.

The second commit makes a custom path that no longer validates fall back to the auto-detected game instead of leaving no game for that session.

Tested on Linux with the Steam version of Spore and GA: with the paths in config.properties, 2.2.27 writes AUTO for both on the next save, this branch keeps them, and an invalid path is still written back as AUTO.