use_sim_timeの順序入れ替え

[YusukeKato]

What does this implement/fix?

demo.launch.pyの実行がuse_sim_timeオプションをつけていないと失敗するため、use_sim_timeの定義とセットの順番を入れ替えます。

Does this close any currently open issues?

しません。

How has this been tested?

下記コマンドが正常に実行できることを確認しました。

ros2 launch sciurus17_examples demo.launch.py use_mock_components:=true

Any other comments?

もとの状態だと下記のエラーが出ます。

$ ros2 launch sciurus17_examples demo.launch.py use_mock_components:=true
...
[ERROR] [launch]: Caught exception in launch (see debug for traceback): launch configuration 'use_sim_time' does not exist

Checklists

• I have read the CONTRIBUTING guidelines.
  • If there is no guideline in the repository, rt-net organization's guideline applies.
• I have checked to ensure there aren't other open Pull Requests for the same change.

[Kuwamai]

LGTMです