message [nfc]: Drop reconcileMessages from main interface

Much like we did with setServerEmojiData in a recent commit,
and for the same reasons: after setServerEmojiData, this was
the only one of our numerous methods on the various FooStore
interfaces where the two different implementations of the method
actually had different behavior.  That's potentially misleading,
so make the two implementations be unrelated methods instead.

Author: gnprice

lib/model/message.dart

@@ -46,23 +46,6 @@ mixin MessageStore {
   /// or [OutboxMessageState.waitPeriodExpired].
   OutboxMessage takeOutboxMessage(int localMessageId);
 
-  /// Reconcile a batch of just-fetched messages with the store,
-  /// mutating the list.
-  ///
-  /// This is called after a [getMessages] request to report the result
-  /// to the store.
-  ///
-  /// The list's length will not change, but some entries may be replaced
-  /// by a different [Message] object with the same [Message.id],
-  /// or mutated to remove [Message.matchContent] and [Message.matchTopic]
-  /// (since these are appropriate for search views but not the central store).
-  /// All [Message] objects in the resulting list will be present in
-  /// [this.messages].
-  ///
-  /// [Message.matchTopic] and [Message.matchContent] should be captured,
-  /// as needed for search, before this is called.
-  void reconcileMessages(List<Message> messages);
-
   /// Whether the current edit request for the given message, if any, has failed.
   ///
   /// Will be null if there is no current edit request.
@@ -249,7 +232,6 @@ class MessageStoreImpl extends HasRealmStore with MessageStore, _OutboxMessageSt
     return _outboxSendMessage(destination: destination, content: content);
   }
 
-  @override
   void reconcileMessages(List<Message> messages) {
     assert(!_disposed);
     // What to do when some of the just-fetched messages are already known?

lib/model/store.dart

@@ -637,12 +637,30 @@ class PerAccountStore extends PerAccountStoreBase with
   @override
   OutboxMessage takeOutboxMessage(int localMessageId) =>
     _messages.takeOutboxMessage(localMessageId);
-  @override
+
+  /// Reconcile a batch of just-fetched messages with the store,
+  /// mutating the list.
+  ///
+  /// This is called after a [getMessages] request to report the result
+  /// to the store.
+  ///
+  /// The list's length will not change, but some entries may be replaced
+  /// by a different [Message] object with the same [Message.id],
+  /// and the store will also be updated.
+  /// When this method returns, all [Message] objects in the list
+  /// will be present in the map `this.messages`.
+  ///
+  /// The list entries may be mutated to remove
+  /// [Message.matchContent] and [Message.matchTopic]
+  /// (since these are appropriate for search views but not the central store).
+  /// The values of those fields should therefore be captured,
+  /// as needed for search, before this is called.
   void reconcileMessages(List<Message> messages) {
     _messages.reconcileMessages(messages);
     // TODO(#649) notify [unreads] of the just-fetched messages
     // TODO(#650) notify [recentDmConversationsView] of the just-fetched messages
   }
+
   @override
   bool? getEditMessageErrorStatus(int messageId) {
     return _messages.getEditMessageErrorStatus(messageId);