fix: Embed disabled state should persist (#3407)

* Normalize code around localStorage
Persist disabled embed state

* fix: Cannot view more than 10 starred items on load

* More tidying of sidebar state

app/utils/Storage.ts

@@ -0,0 +1,56 @@
+/**
+ * Storage is a wrapper class for localStorage that allow safe usage when
+ * localStorage is not available.
+ */
+export default class Storage {
+  /**
+   * Set a value in localStorage. For efficiency, this method will remove the
+   * value if it is undefined.
+   *
+   * @param key The key to set under.
+   * @param value The value to set
+   */
+  static set<T>(key: string, value: T) {
+    try {
+      if (value === undefined) {
+        this.remove(key);
+      } else {
+        localStorage.setItem(key, JSON.stringify(value));
+      }
+    } catch (error) {
+      // no-op Safari private mode
+    }
+  }
+
+  /**
+   * Get a value from localStorage.
+   *
+   * @param key The key to get.
+   * @returns The value or undefined if it doesn't exist.
+   */
+  static get(key: string) {
+    try {
+      const value = localStorage.getItem(key);
+      if (typeof value === "string") {
+        return JSON.parse(value);
+      }
+    } catch (error) {
+      // no-op Safari private mode
+    }
+
+    return undefined;
+  }
+
+  /**
+   * Remove a value from localStorage.
+   *
+   * @param key The key to remove.
+   */
+  static remove(key: string) {
+    try {
+      localStorage.removeItem(key);
+    } catch (error) {
+      // no-op Safari private mode
+    }
+  }
+}