adds migration to remove system sources with a type of rejected_events to align with changes to ecto enum in commit 0350b23 (#3014)

Author: amokan

priv/repo/migrations/20251205181853_remove_rejected_event_system_sources.exs

@@ -0,0 +1,11 @@
+defmodule Logflare.Repo.Migrations.RemoveRejectedEventSystemSources do
+  use Ecto.Migration
+
+  def up do
+    execute("DELETE FROM sources WHERE system_source_type = 'rejected_events'")
+  end
+
+  def down do
+    :ok
+  end
+end