feat(migration): ubah kolom jenis_lampiran_id menjadi nullable

- Mengubah kolom jenis_lampiran_id pada tabel lampiran_dokumen agar dapat bernilai null.
- Memastikan integritas data saat penghapusan jenis lampiran dengan opsi onDelete cascade.

database/migrations/2025_03_14_013537_add_jenis_lampiran_id_to_lampiran_dokumen_table.php

@@ -13,7 +13,7 @@ use Illuminate\Support\Facades\Schema;
     public function up(): void
     {
         Schema::table('lampiran_dokumen', function (Blueprint $table) {
-           $table->foreignIdFor(JenisLampiran::class)->constrained('jenis_lampiran')->onDelete('cascade');
+           $table->foreignIdFor(JenisLampiran::class)->constrained('jenis_lampiran')->onDelete('cascade')->nullable();
         });
     }