fix: avoid exception in Changeset.new/2 for bad attribute

lib/ash/changeset/changeset.ex

@@ -1576,11 +1576,6 @@ defmodule Ash.Changeset do
             name: attribute
           )
 
-        changeset = %{
-          changeset
-          | attributes: Map.put(changeset.attributes, attribute.name, value)
-        }
-
         add_error(changeset, error)
 
       %{writable?: false} = attribute ->

test/changeset/changeset_test.exs

@@ -433,6 +433,16 @@ defmodule Ash.Test.Changeset.ChangesetTest do
                    end
     end
 
+    test "if an attribute does not exist in `new/2`, a corresponding error is added`" do
+      error =
+        Author
+        |> Changeset.new(%{"flarb" => 10})
+        |> Map.get(:errors)
+        |> Enum.at(0)
+
+      assert %Ash.Error.Changes.NoSuchAttribute{name: "flarb"} = error
+    end
+
     test "it destroys related records if not present" do
       post1 = %{title: "title"}
       post2 = %{title: "title"}