Save default panel at user and system level (#27899)

* Save default panel in user data

* Change logic for default panel

* Fix types

* Fix typings

* Fix user and local storage

* Use user data and system data

* Update url path and update dashboard settings

* Fix tests

* Wait for panels and user/system data to be loaded

* Update comment

* Update comment

* Set empty object instead of null

* Update comment

* Feedbacks

* Apply suggestions from code review

* format

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Co-authored-by: Petar Petrov <MindFreeze@users.noreply.github.com>

test/util/ha-pref-storage.test.ts

@@ -24,7 +24,7 @@ describe("ha-pref-storage", () => {
     window.localStorage.setItem = vi.fn();
 
     storeState(mockHass as unknown as HomeAssistant);
-    expect(window.localStorage.setItem).toHaveBeenCalledTimes(8);
+    expect(window.localStorage.setItem).toHaveBeenCalledTimes(7);
     expect(window.localStorage.setItem).toHaveBeenCalledWith(
       "dockedSidebar",
       JSON.stringify("auto")