app: [android] fix compatibility with older Android versions

Previously, setHighRefreshRate requires APIs restricted
to Android 30, or higher.

Tested on Android 6.0.1 (released on 2015).

Author: inkeliz

app/GioView.java

@@ -260,6 +260,10 @@ private void setNavigationColor(int color, int luminance) {
 	}
 
 	private void setHighRefreshRate() {
+		if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) {
+			return;
+		}
+
 		Context context = getContext();
 		Display display = context.getDisplay();
 		Display.Mode[] supportedModes = display.getSupportedModes();