Use IndexablePresence for hasFileAttachments and hasVisualMediaAttachments

Reduces index size, makes it easier to debug using IndexedDB inspector, and
hopefully improves lookup performance.

js/modules/migrations/18/index.js

@@ -1,15 +1,18 @@
 exports.run = (transaction) => {
   const messagesStore = transaction.objectStore('messages');
 
-  [
+  console.log("Create message attachment metadata index: 'hasAttachments'");
+  messagesStore.createIndex(
     'hasAttachments',
-    'hasVisualMediaAttachments',
-    'hasFileAttachments',
-  ].forEach((name) => {
+    ['conversationId', 'hasAttachments', 'received_at'],
+    { unique: false }
+  );
+
+  ['hasVisualMediaAttachments', 'hasFileAttachments'].forEach((name) => {
     console.log(`Create message attachment metadata index: '${name}'`);
     messagesStore.createIndex(
       name,
-      ['conversationId', name, 'received_at'],
+      ['conversationId', 'received_at', name],
       { unique: false }
     );
   });

js/modules/types/message.js

@@ -25,9 +25,8 @@ const PRIVATE = 'private';
 // Version 5
 //   - Attachments: Track number and kind of attachments for media gallery
 //     - `hasAttachments?: 1 | 0`
-//     - `hasVisualMediaAttachments?: 1 | 0` (for media gallery ‘Media’ view)
-//     - `hasFileAttachments?: 1 | 0` (for media gallery ‘Documents’ view)
-
+//     - `hasVisualMediaAttachments?: 1 | undefined` (for media gallery ‘Media’ view)
+//     - `hasFileAttachments?: 1 | undefined` (for media gallery ‘Documents’ view)
 
 const INITIAL_SCHEMA_VERSION = 0;