Fix a few pinned chat sync issues

ts/ConversationController.ts

@@ -732,4 +732,37 @@ export class ConversationController {
 
     return this._initialPromise;
   }
+
+  getPinnedConversationIds(): Array<string> {
+    let pinnedConversationIds = window.storage.get<Array<string>>(
+      'pinnedConversationIds'
+    );
+
+    // If pinnedConversationIds is missing, we're upgrading from
+    // a previous version and need to backfill storage from pinned
+    // conversation models.
+    if (pinnedConversationIds === undefined) {
+      window.log.info(
+        'getPinnedConversationIds: no pinned conversations in storage'
+      );
+
+      const modelPinnedConversationIds = this._conversations
+        .filter(conversation => conversation.get('isPinned'))
+        // pinIndex is a deprecated field. We now rely on the order of
+        // the ids in storage, which is synced with the AccountRecord.
+        // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+        // @ts-ignore
+        .sort((a, b) => (a.get('pinIndex') || 0) - (b.get('pinIndex') || 0))
+        .map(conversation => conversation.get('id'));
+
+      window.log.info(
+        `getPinnedConversationIds: falling back to ${modelPinnedConversationIds.length} pinned models`
+      );
+
+      window.storage.put('pinnedConversationIds', modelPinnedConversationIds);
+      pinnedConversationIds = modelPinnedConversationIds;
+    }
+
+    return pinnedConversationIds;
+  }
 }