Migration: make `goals.custom_props` non-null (#5945)

priv/repo/migrations/20251211110619_goals_custom_props_default.exs

@@ -0,0 +1,9 @@
+defmodule Plausible.Repo.Migrations.GoalsCustomPropsDefault do
+  use Ecto.Migration
+
+  def change do
+    alter table(:goals) do
+      modify(:custom_props, :map, null: false, default: %{})
+    end
+  end
+end