feat(cockpit): render the Contact and briefing cards' collapse from the store

Cockpit presence now carries contextCollapsed and signalCollapsed.
setContextCollapsed and setSignalCollapsed update presence and republish
it only when the value changes, instead of writing the dataset and the
toggle attributes. CockpitContext and CockpitBriefing bind data-collapsed
and their toggles' aria-expanded, aria-label, title and icon from
presence. The Cockpit utility QA script waits a frame for Vue to render
before it reads the toggles.

src/cockpitMarkup.test.mjs

@@ -1197,9 +1197,13 @@ test('cockpit summary presents the focused item as Contact', () => {
   );
   assert.match(match[0], /aria-label="Collapse Contact panel"/);
   assert.doesNotMatch(match[0], />GLOBAL CONTEXT</);
+  // The toggle renders the collapse the controller presents.
   assert.match(
-    setContextCollapsed.toString(),
-    /expanded \? t\('Collapse Contact panel'\) : t\('Expand Contact panel'\)/,
+    fs.readFileSync(
+      new URL('./ui/views/panels/CockpitContext.vue', import.meta.url),
+      'utf8',
+    ),
+    /collapsed \? t\('Expand Contact panel'\) : t\('Collapse Contact panel'\)/,
   );
 });