MRF.HashtagPolicy: fix dialyzer error

lib/pleroma/web/activity_pub/mrf/hashtag_policy.ex:87:exact_eq
The test <<_::32>> == <<_::48>> can never evaluate to 'true'.

changelog.d/mrf_hashtags.fix

@@ -0,0 +1 @@
+Federated timeline removal of hashtags via MRF HashtagPolicy

lib/pleroma/web/activity_pub/mrf/hashtag_policy.ex

@@ -84,7 +84,7 @@ def filter(%{"type" => type, "object" => object} = message) when type in ["Creat
     if hashtags != [] do
       with {:ok, message} <- check_reject(message, hashtags),
            {:ok, message} <-
-             (if "type" == "Create" do
+             (if type == "Create" do
                 check_ftl_removal(message, hashtags)
               else
                 {:ok, message}