[FIX] im_livechat: fix message unread counter

Since [1], the way the message unread counter is computed has changed.
The patch of the `im_livechat` module is not adapted properly. This
commit fixes this issue.

[1]: 6ebe033b00774ed8824d05f0adf9dae5f3654261

closes odoo/odoo#118581

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/im_livechat/static/src/core/thread_service_patch.js

@@ -51,7 +51,7 @@ patch(ThreadService.prototype, "im_livechat", {
 
     getCounter(thread) {
         if (thread.type === "livechat") {
-            return thread.message_needaction_counter;
+            return thread.message_unread_counter;
         }
         return this._super(thread);
     },

addons/im_livechat/static/tests/sidebar_patch_tests.js

@@ -449,3 +449,28 @@ QUnit.test("Clicking on unpin button unpins the channel", async (assert) => {
     await click(".o-mail-DiscussCategoryItem [title='Unpin Conversation']");
     assert.verifySteps(["You unpinned your conversation with Visitor 11"]);
 });
+
+QUnit.test("Message unread counter", async (assert) => {
+    const pyEnv = await startServer();
+    const partnerId = pyEnv["res.partner"].create({ name: "Harry" });
+    const userId = pyEnv["res.users"].create({ name: "Harry", partner_id: partnerId });
+    const channelId = pyEnv["mail.channel"].create({
+        anonymous_name: "Visitor 11",
+        channel_member_ids: [
+            [0, 0, { partner_id: pyEnv.currentPartnerId }],
+            [0, 0, { partner_id: pyEnv.publicPartnerId }],
+        ],
+        channel_type: "livechat",
+        livechat_operator_id: pyEnv.currentPartnerId,
+    });
+    const { env, openDiscuss } = await start();
+    await openDiscuss();
+    await afterNextRender(async () =>
+        env.services.rpc("/mail/chat_post", {
+            context: { mockedUserId: userId },
+            message_content: "hu",
+            uuid: pyEnv["mail.channel"].searchRead([["id", "=", channelId]])[0].uuid,
+        })
+    );
+    assert.containsOnce($, ".o-mail-DiscussCategoryItem .badge:contains(1)");
+});