Mastodon API: Fix thread mute detection

It was calling CommonAPI.thread_muted? with post author's account
instead of viewer's one.

CHANGELOG.md

@@ -6,6 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [1.0.5] - 2019-08-??
 ### Fixed
 - Mastodon API: follower/following counters not being nullified, when `hide_follows`/`hide_followers` is set
+- Mastodon API: `muted` in the Status entity, using author's account to determine if the thread was muted
 
 ## [1.0.4] - 2019-08-01
 ### Fixed

lib/pleroma/web/mastodon_api/views/status_view.ex

@@ -160,7 +160,7 @@ def render("status.json", %{activity: %{data: %{"object" => _object}} = activity
     thread_muted? =
       case activity.thread_muted? do
         thread_muted? when is_boolean(thread_muted?) -> thread_muted?
-        nil -> CommonAPI.thread_muted?(user, activity)
+        nil -> (opts[:for] && CommonAPI.thread_muted?(opts[:for], activity)) || false
       end
 
     attachment_data = object.data["attachment"] || []

test/web/mastodon_api/mastodon_api_controller_test.exs

@@ -2684,8 +2684,10 @@ test "bookmarks" do
 
   describe "conversation muting" do
     setup do
+      post_user = insert(:user)
       user = insert(:user)
-      {:ok, activity} = CommonAPI.post(user, %{"status" => "HIE"})
+
+      {:ok, activity} = CommonAPI.post(post_user, %{"status" => "HIE"})
 
       [user: user, activity: activity]
     end