wrapped original funtion may gets destroyed before usage

For #564

lib/extension.js

@@ -157,14 +157,19 @@
 			});
 		}
 		const handler = scope.getWrapped(window).Object.create(null);
-		handler.apply = scope.exportFunctionWithName(function(_target, thisArgs, args){
+		handler.apply = scope.exportFunctionWithName(function(target, thisArgs, args){
 			try {
 				return args.length?
 					replacement.call(thisArgs, ...args):
 					replacement.call(thisArgs);
 			}
 			catch (error){
-				return original.apply(thisArgs, args);
+				try {
+					return original.apply(thisArgs, args);
+				}
+				catch (error){
+					return target.apply(thisArgs, args);
+				}
 			}
 		}, window, "");
 		const proxy = new window.Proxy(original, handler);

versions/updates.json

@@ -197,6 +197,10 @@
 				{
 					"version": "1.7Alpha20210620",
 					"update_link": "https://canvasblocker.kkapsner.de/versions/canvasblocker_beta-1.7Alpha20210620-an+fx.xpi"
+				},
+				{
+					"version": "1.7Alpha20210621",
+					"update_link": "https://canvasblocker.kkapsner.de/versions/canvasblocker_beta-1.7Alpha20210621-an+fx.xpi"
 				}
 			]
 		}