Fix order of args for unblock/2

lib/pleroma/web/common_api.ex

@@ -100,7 +100,7 @@ defp validate_chat_content_length(content, _) do
   end
 
   @spec unblock(User.t(), User.t()) :: {:ok, Activity.t()} | {:error, any()}
-  def unblock(blocker, blocked) do
+  def unblock(blocked, blocker) do
     with {_, %Activity{} = block} <- {:fetch_block, Utils.fetch_latest_block(blocker, blocked)},
          {:ok, unblock_data, _} <- Builder.undo(blocker, block),
          {:ok, unblock, _} <- Pipeline.common_pipeline(unblock_data, local: true) do

lib/pleroma/web/mastodon_api/controllers/account_controller.ex

@@ -504,7 +504,7 @@ def block(%{assigns: %{user: blocker, account: blocked}} = conn, _params) do
 
   @doc "POST /api/v1/accounts/:id/unblock"
   def unblock(%{assigns: %{user: blocker, account: blocked}} = conn, _params) do
-    with {:ok, _activity} <- CommonAPI.unblock(blocker, blocked) do
+    with {:ok, _activity} <- CommonAPI.unblock(blocked, blocker) do
       render(conn, "relationship.json", user: blocker, target: blocked)
     else
       {:error, message} -> json_response(conn, :forbidden, %{error: message})

test/pleroma/web/common_api_test.exs

@@ -324,7 +324,7 @@ test "it works even without an existing block activity" do
       User.block(blocker, blocked)
 
       assert User.blocks?(blocker, blocked)
-      assert {:ok, :no_activity} == CommonAPI.unblock(blocker, blocked)
+      assert {:ok, :no_activity} == CommonAPI.unblock(blocked, blocker)
       refute User.blocks?(blocker, blocked)
     end
   end