Elixir 1.18 Remove seemingly unneeded cond

warning: this clause in cond will always match:

<<"#", name::binary>>

since it has type:

binary()

where "name" was given the type:

%{"type" => "Hashtag", "name" => name} = data

   typing violation found at:
   │
55 │         "#" <> name -> name
   │                     ~
   │
   └─ lib/pleroma/web/activity_pub/object_validators/tag_validator.ex:55:21: Pleroma.Web.ActivityPub.ObjectValidators.TagValidator.changeset/2

lib/pleroma/web/activity_pub/object_validators/tag_validator.ex

@@ -50,12 +50,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.TagValidator do
   end
 
   def changeset(struct, %{"type" => "Hashtag", "name" => name} = data) do
-    name =
-      cond do
-        "#" <> name -> name
-        name -> name
-      end
-      |> String.downcase()
+    name = String.downcase(name)
 
     data = Map.put(data, "name", name)