refactor(validity-time): remove 'active' field from ValidityTime model and related migrations/tests

database/migrations/2026_08_06_000100_create_validity_times_table.php

@@ -15,7 +15,6 @@ return new class extends Migration
             $table->time('end_time')->nullable();
             $table->dateTime('fixed_starts_at')->nullable();
             $table->dateTime('fixed_expires_at')->nullable();
-            $table->boolean('active')->default(true);
             $table->timestamps();
         });
     }

database/migrations/2026_08_06_000400_remove_legacy_ticket_validity_columns.php

@@ -70,7 +70,6 @@ return new class extends Migration
                     'end_time' => null,
                     'fixed_starts_at' => $startsAt,
                     'fixed_expires_at' => $expiresAt,
-                    'active' => true,
                     'created_at' => now(),
                     'updated_at' => now(),
                 ]);