Fix WEC shutting down on error

When the WEC can't go to the page it was directed to it throws an error instead of killing the process. This helps us in the WEC Online to recover from failure.

src/collector/index.ts

@@ -132,7 +132,7 @@ export class Collector {
     const response = await this.pageSession.gotoPage(url);
 
     if (response == null) {
-      process.exit(2);
+      throw new Error("The collector was not able to access the page.");
     }
 
     // log redirects