jsonrpc: add fresh message count to the archive-link chatlistitem variant (#3920)

this is a followup to #3918

I went with option "C" from my comment:
https://github.com/deltachat/deltachat-core-rust/pull/3918#issuecomment-1371224339

- Archive link is (still) very different from a normal chat, so most of the options would be empty / not relevant
- avatar path is not needed as desktop renders it differently anyway,
it's not really a chat like saved messages or device messages where it made more sense
for the core to supply the icon, vs. using the svg directly.
- translating the string in the coreas stock-string is more annoying than doing it from the ui, especially when
this special pseudo chat has different rendering anyway so also no need to provide a name property

deltachat-jsonrpc/src/api/types/chat_list.rs

@@ -48,12 +48,10 @@ pub enum ChatListItemFetchResult {
         dm_chat_contact: Option<u32>,
         was_seen_recently: bool,
     },
-    ArchiveLink,
     #[serde(rename_all = "camelCase")]
-    Error {
-        id: u32,
-        error: String,
-    },
+    ArchiveLink { fresh_message_counter: usize },
+    #[serde(rename_all = "camelCase")]
+    Error { id: u32, error: String },
 }
 
 pub(crate) async fn get_chat_list_item_by_id(
@@ -66,8 +64,12 @@ pub(crate) async fn get_chat_list_item_by_id(
         _ => Some(MsgId::new(entry.1)),
     };
 
+    let fresh_message_counter = chat_id.get_fresh_msg_cnt(ctx).await?;
+
     if chat_id.is_archived_link() {
-        return Ok(ChatListItemFetchResult::ArchiveLink);
+        return Ok(ChatListItemFetchResult::ArchiveLink {
+            fresh_message_counter,
+        });
     }
 
     let chat = Chat::load_from_db(ctx, chat_id).await?;
@@ -111,7 +113,6 @@ pub(crate) async fn get_chat_list_item_by_id(
         (None, false)
     };
 
-    let fresh_message_counter = chat_id.get_fresh_msg_cnt(ctx).await?;
     let color = color_int_to_hex_string(chat.get_color(ctx).await?);
 
     Ok(ChatListItemFetchResult::ChatListItem {