Remove unnecessary namespace from generated Cest

EndToEnd tester is created to use EndToEndTester
with a Test\Support namespace which throws an
error because EndToEnd tester does not have a
namespace.

src/Project/PluginProject.php

@@ -147,7 +147,7 @@ protected function scaffoldEndToEndActivationCest(): void
 
 namespace Tests\\EndToEnd;
 
-use Tests\\Support\\EndToEndTester;
+use EndToEndTester;
 
 class ActivationCest
 {