tests: Reduce dependency on #host-toggle

`#hosts-sel` will stay for showing the current user/host, but the toggle
will go away by default when we deprecate the host switcher.

The only remaining reference to it is in `testKeyboardNavigation` now,
which is intrinsically necessary. That test will have to be adjusted
when we actually disable the host switcher.

test/verify/check-client

@@ -62,7 +62,7 @@ Command = /usr/bin/env python3 -m cockpit.beiboot
     def check_login(self, expected_user):
         b = self.browser
         b.wait_visible('#content')
-        b.wait_in_text("#host-toggle", expected_user)
+        b.wait_in_text("#hosts-sel", expected_user)
         b.enter_page("/system")
         if self.is_devel_build():
             b.wait_visible("#system_information_hostname_text")

test/verify/check-shell-menu

@@ -163,7 +163,7 @@ class TestMenu(testlib.MachineCase):
         self.login_and_go()
 
         # initially shows host switcher
-        b.wait_visible("#host-toggle")
+        b.wait_visible("#hosts-sel")
         self.assertEqual(b.eval_js("document.activeElement.tagName"), "BODY")
         # conceptually we want that, but we use CSS hacks (-999 offset and 1x1 size) to hide it
         # b.wait_not_visible(".skiplink")
@@ -180,7 +180,7 @@ class TestMenu(testlib.MachineCase):
 
         # reset
         b.reload()
-        b.wait_visible("#host-toggle")
+        b.wait_visible("#hosts-sel")
 
         # press Tab twice → "Skip main navigation" skiplink
         b.key("Tab")
@@ -202,7 +202,7 @@ class TestMenu(testlib.MachineCase):
 
         # reset
         b.reload()
-        b.wait_visible("#host-toggle")
+        b.wait_visible("#hosts-sel")
 
         # without skip links, tabbing goes through page menu
         b.key("Tab", repeat=5)