test/e2e: podman unshare image mount fix tmpdir leak

Because the test left the image mounted the cleanup failed to remove the
tmpdir as it contained an active mount point. Thus ensure we unmount the
image again to prevent this leak.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

test/e2e/mount_rootless_test.go

@@ -1,6 +1,8 @@
 package integration
 
 import (
+	"slices"
+
 	. "github.com/containers/podman/v5/test/utils"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
@@ -63,5 +65,14 @@ var _ = Describe("Podman mount", func() {
 		session.WaitWithDefaultTimeout()
 		Expect(session).Should(ExitCleanly())
 		Expect(session.OutputToString()).To(ContainSubstring(podmanTest.TempDir))
+
+		// We have to unmount the image again otherwise we leak the tmpdir
+		// as active mount points cannot be removed.
+		index := slices.Index(args, "mount")
+		Expect(index).To(BeNumerically(">", 0), "index should be found")
+		args[index] = "unmount"
+		session = podmanTest.Podman(args)
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(ExitCleanly())
 	})
 })