IOS: Add back new delegate methods but keep old ones

On iOS 12 and below, the one delegate methods are called. On iOS13.2
and above if both sets are implemented only the new delegate methods
are called, which prevent getting the deprecation warning.

backends/platform/ios7/ios7_app_delegate.mm

@@ -118,6 +118,16 @@
 	return YES;
 }
 
+#ifdef __IPHONE_13_2
+- (BOOL)application:(UIApplication *)application shouldSaveSecureApplicationState:(NSCoder *)coder {
+	return YES;
+}
+
+- (BOOL)application:(UIApplication *)application shouldRestoreSecureApplicationState:(NSCoder *)coder {
+	return YES;
+}
+#endif
+
 - (void)application:(UIApplication *)application didDecodeRestorableStateWithCoder:(NSCoder *)coder {
 	_restoreState = YES;
 }