test: Only run alert and logout cleanups if Cockpit is actually opened

Some tests like `testAddDiskNFS` fail during setup [1], so the test
teardown runs while the browser still shows a blank page.

Use the new `Browser.have_test_api()` from
cockpit-project/cockpit#21349 instead of merely
checking if the browser is running to clean that up.

[1] cockpit-project/bots#7137

Makefile

@@ -41,7 +41,7 @@ COCKPIT_REPO_FILES = \
 	$(NULL)
 
 COCKPIT_REPO_URL = https://github.com/cockpit-project/cockpit.git
-COCKPIT_REPO_COMMIT = 7090fab7372ef7e87e508d207e6468ba76983f9f # 329 + 58 commits
+COCKPIT_REPO_COMMIT = b453940e6a7cde684832d750ba56d4afd44a699e # 329 + 66 commits
 
 $(COCKPIT_REPO_FILES): $(COCKPIT_REPO_STAMP)
 COCKPIT_REPO_TREE = '$(strip $(COCKPIT_REPO_COMMIT))^{tree}'

test/machineslib.py

@@ -494,7 +494,7 @@ def stop_all():
             self.allow_journal_messages(r".* couldn't get all properties of org.freedesktop.NetworkManager.Device at /org/freedesktop/NetworkManager/Devices/\d+: Timeout was reached")  # noqa: E501
 
         # avoid error noise about resources getting cleaned up
-        self.addCleanup(lambda: not self.browser.valid or self.browser.logout())
+        self.addCleanup(lambda: not self.browser.have_test_api() or self.browser.logout())
 
         # noVNC warns about this for non-TLS connections; for RHEL downstream testing
         self.allow_browser_errors("noVNC requires a secure context")
@@ -557,7 +557,7 @@ def downloadVmsArtifacts(self):
 
     def tearDown(self):
         b = self.browser
-        if b.valid and b.is_present("#button.alert-link.more-button"):
+        if b.have_test_api() and b.is_present("#button.alert-link.more-button"):
             b.click("button.alert-link.more-button")
 
         if self.getError():