Add cleanup

Author: beena352

test/windows/wslc/e2e/WSLCE2EContainerCreateTests.cpp

@@ -943,10 +943,16 @@ class WSLCE2EContainerCreateTests
             GetPythonHttpServerScript(ContainerTestPort)));
         result1.Verify({.Stderr = L"", .ExitCode = 0});
 
+        auto containersBefore = ListAllContainers().size();
+
         // Attempt to start another container mapping the same host port
         auto result2 = RunWslc(std::format(L"container run -p {}:{} {}", HostTestPort1, ContainerTestPort, DebianImage.NameAndTag()));
         result2.Verify({.ExitCode = 1});
         VERIFY_IS_TRUE(result2.Stderr.has_value() && result2.Stderr.value().find(L"is already in use") != std::wstring::npos);
+
+        // Verify the failed container was not left behind
+        auto containersAfter = ListAllContainers().size();
+        VERIFY_ARE_EQUAL(containersBefore, containersAfter);
     }
 
     // https://github.com/microsoft/WSL/issues/14433