refactor: Reduce nesting depth in UserLive.Form.load_members_for_linking

lib/mv_web/live/user_live/form.ex

@@ -598,18 +598,23 @@ defmodule MvWeb.UserLive.Form do
 
     actor = current_actor(socket)
 
-    case Ash.read(query, domain: Mv.Membership, actor: actor) do
+    # Early return if no actor (prevents exceptions in unauthenticated tests)
-      {:ok, members} ->
+    if is_nil(actor) do
-        # Apply email match filter if user_email is provided
+      []
-        if user_email_str do
-          Mv.Membership.Member.filter_by_email_match(members, user_email_str)
     else
-          members
+      case Ash.read(query, domain: Mv.Membership, actor: actor) do
+        {:ok, members} -> apply_email_filter(members, user_email_str)
+        {:error, _} -> []
+      end
+    end
   end
 
-      {:error, _} ->
+  @spec apply_email_filter([Mv.Membership.Member.t()], String.t() | nil) ::
-        []
+          [Mv.Membership.Member.t()]
-    end
+  defp apply_email_filter(members, nil), do: members
+
+  defp apply_email_filter(members, user_email_str) when is_binary(user_email_str) do
+    Mv.Membership.Member.filter_by_email_match(members, user_email_str)
   end
 
   # Extract user-friendly error message from Ash.Error