Bug Fixes + Element Change Appearance Rate Adjustment

Fixed a bug where pressing the "Back" button from the owned cards screen would lead to a gray screen.
Adjusted the appearance rate of Element Change. Element Change will now appear more frequently than before. Although the increase is slight, it’s balanced so that consecutive appearances can still happen. Occasionally, Element Change might appear too frequently, but this also makes it easier to switch to higher-level ones. Please make good use of this in your strategy!