A few fixes comming from Dialyser

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

Fixes

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon_web/api/groups.ex

@@ -51,7 +51,7 @@ defmodule MobilizonWeb.API.Groups do
       {:existing_group, _} ->
         {:error, :existing_group_name}
 
-      {:bad_actor} ->
+      {:bad_actor, _} ->
         {:error, :bad_admin_actor}
     end
   end

lib/mobilizon_web/http_signature.ex

@@ -32,8 +32,7 @@ defmodule MobilizonWeb.HTTPSignaturePlug do
     [signature | _] = get_req_header(conn, "signature")
 
     cond do
-      # Dialyzer doesn't like this line
-      signature && String.contains?(signature, actor) ->
+      String.contains?(signature, actor) ->
         conn =
           conn
           |> put_req_header(